U.S. patent application number 11/652364 was filed with the patent office on 2007-05-31 for foldable prosthetic implant element.
This patent application is currently assigned to Discure Limited. Invention is credited to Amiram Steinberg.
Application Number | 20070123991 11/652364 |
Document ID | / |
Family ID | 27407259 |
Filed Date | 2007-05-31 |
United States Patent
Application |
20070123991 |
Kind Code |
A1 |
Steinberg; Amiram |
May 31, 2007 |
Foldable prosthetic implant element
Abstract
The present invention seeks to provide improved joint implants
and methods relating to joint implantation. An embodiment is
described wherein an implant is constructed of a resilient material
which may be deformed to facilitate implantation and final fixation
at the joint.
Inventors: |
Steinberg; Amiram; (Avihail,
IL) |
Correspondence
Address: |
KELLEY DRYE & WARREN LLP
400 ATLANTIC STREET
13TH FLOOR
STAMFORD
CT
06901
US
|
Assignee: |
Discure Limited
Moshav Avihail
IL
|
Family ID: |
27407259 |
Appl. No.: |
11/652364 |
Filed: |
January 11, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10497897 |
Nov 15, 2004 |
|
|
|
PCT/IL02/00972 |
Dec 3, 2002 |
|
|
|
11652364 |
Jan 11, 2007 |
|
|
|
60338349 |
Dec 4, 2001 |
|
|
|
60351755 |
Jan 24, 2002 |
|
|
|
60383483 |
May 23, 2002 |
|
|
|
Current U.S.
Class: |
623/18.11 |
Current CPC
Class: |
A61F 2/3872 20130101;
A61F 2/4609 20130101; A61F 2220/0025 20130101; A61F 2230/0017
20130101; A61F 2/3662 20130101; A61F 2002/3605 20130101; A61F
2230/0019 20130101; A61B 17/1666 20130101; A61F 2/4081 20130101;
A61F 2002/30291 20130101; A61L 27/18 20130101; A61B 17/1684
20130101; A61F 2/3877 20130101; A61F 2/40 20130101; A61F 2002/30322
20130101; A61F 2002/3008 20130101; A61F 2002/30574 20130101; A61F
2002/4029 20130101; A61F 2310/00407 20130101; A61F 2002/30652
20130101; A61F 2002/3425 20130101; A61F 2250/0026 20130101; A61F
2/30965 20130101; A61F 2002/3081 20130101; A61F 2002/30906
20130101; A61F 2002/30971 20130101; A61F 2002/30112 20130101; A61F
2250/0036 20130101; A61F 2/3609 20130101; A61F 2/4059 20130101;
A61F 2002/30332 20130101; A61F 2002/30823 20130101; A61F 2002/342
20130101; A61F 2002/3459 20130101; A61F 2002/3611 20130101; A61F
2002/3831 20130101; A61F 2002/3895 20130101; A61F 2/30724 20130101;
A61F 2002/30892 20130101; A61F 2002/4007 20130101; A61F 2230/0091
20130101; A61F 2310/00796 20130101; A61F 2/30771 20130101; A61F
2/38 20130101; A61F 2002/4018 20130101; A61F 2/34 20130101; A61F
2002/30324 20130101; A61F 2002/30883 20130101; A61F 2002/4037
20130101; A61F 2/3804 20130101; A61F 2/4014 20130101; A61F
2002/30822 20130101; A61F 2/4003 20130101; A61F 2/3094 20130101;
A61F 2/32 20130101; A61F 2002/3071 20130101; A61F 2230/0093
20130101; A61F 2/4607 20130101; A61F 2/30767 20130101; A61F
2002/30069 20130101; A61F 2002/3007 20130101; A61F 2002/30299
20130101; A61F 2002/30934 20130101; A61F 2002/3443 20130101; A61F
2002/3827 20130101; A61F 2/30907 20130101; A61F 2002/30016
20130101; A61F 2002/305 20130101; A61F 2002/3822 20130101; A61F
2002/4062 20130101; A61F 2310/00011 20130101; A61F 2002/30884
20130101; A61F 2002/30957 20130101; A61F 2002/3412 20130101; A61F
2/36 20130101; A61F 2002/30673 20130101; A61F 2250/0019 20130101;
A61F 2002/30143 20130101; A61F 2002/30881 20130101; A61F 2002/4077
20130101; A61F 2002/4627 20130101; A61F 2250/0089 20130101; A61L
2430/24 20130101; A61F 2002/30813 20130101; A61F 2002/3625
20130101; A61F 2/367 20130101; A61F 2002/30937 20130101; A61F
2002/365 20130101; A61F 2250/0098 20130101; A61F 2/3603 20130101;
A61F 2002/30153 20130101; A61F 2310/00179 20130101; A61F 2220/0033
20130101; A61L 27/50 20130101; A61F 2002/30593 20130101; A61F
2002/30894 20130101; A61F 2230/0004 20130101; A61L 27/18 20130101;
C08L 75/04 20130101 |
Class at
Publication: |
623/018.11 |
International
Class: |
A61F 2/30 20060101
A61F002/30 |
Claims
1. A foldable prosthetic implant element, for use in repairing a
joint between two bone structures, constructed of a resilient
material having an first surface and a second surface, said first
surface is operatively configured to fixedly engage one of two said
bone structures, said second surface is operatively configured to
provide an articulation surface, said prosthetic implant element
being deformable from initial physical configuration, using
finger-tip pressure, so as to permit the reduction the geometrical
dimensions of said implant element during implantation, said
prosthetic implant element, returnable to said initial physical
configuration in response to release of said finger-tip pressure.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation application of U.S. Patent
Application Ser. No. 10/497,897, filed Dec. 3, 2002, which claims
priority from U.S. Provisional Patent Application Ser. Nos.
60/338,349, filed Dec. 4, 2001, 60/351,755, filed Jan. 24, 2002 and
60/383,483, filed May 23, 2002, and PCT/IL02/00972, filed Dec. 3,
2002. The disclosure of each such application is hereby
incorporated by reference in its entirety where appropriate for
teachings of additional or alternative details, features, and/or
technical background, and priority is asserted from each.
FIELD OF THE INVENTION
[0002] The present invention relates generally to joint implants
and methods relating thereto.
BACKGROUND OF THE INVENTION
[0003] The following patents are believed to be relevant to the
subject matter of this application.
[0004] U.S. Pat. Nos. 5,201,881; 5,011,497; 4,279,041; 5,080,675;
4,650,491; 3,938,198; 4,292,695; 4,624,674; 2,765,787; 4,735,625;
5,370,699; 5,641,323; 5,323,765; 5,658,345; 3,875,594; 3,938,198;
4,292,695; 4,344,193; 4,570,270; 4,650,491; 4,279,041; 4,661,112;
4,662,889; 4,664,668; 4,715,859; 4,795,470; 4,795,474; 4,808,186;
4,813,962; 4,822,365; 4,888,020; 4,904,269; 4,908,035; 4,919,674;
4,919,678; 4,936,856; 4,938,771; 4,938,773; 4,950,298; 4,955,912;
4,955,919; 4,963,153; 4,963,154; 4,997,447; 5,002,581; 5,019,107;
5,041,140; 5,049,393; 5,080,677; 5,108,446; 5,108,451; 5,116,374;
5,133,763; 5,146,933; 5,147,406; 5,151,521; 5,156,631; 5,171,276;
5,181,925; 5,197,987; 5,197,989; 5,201,881; 5,201,882; 5,217,498;
5,217,499; 5,222,985; 5,282,868; 5,290,314; 5,314,478; 5,314,494;
5,316,550; 5,326,376; 5,330,534; 5,314,493; 5,336,268; 5,344,459;
5,358,525; 5,370,699; 5,376,064; 5,376,125; 5,387,244; 5,389,107;
5,405,403; 5,405,411; 5,415,662; 5,425,779; 5,448,489; 5,458,643;
5,458,651; 5,489,311; 5,491,882; 5,507,814; 5,507,818; 5,507,820;
5,507,823; 5,507,830; 5,507,833; 5,507,836; 5,514,182; 5,514,184;
5,522,904; 5,507,835; 5,246,461; 5,364,839; 5,376,120; 5,393,739;
5,480,449; 5,510,418; 5,522,894; 4,892,551; 5,660,225; 4,089,071;
5,281,226; 5,443,383; 5,480,437; 5,032,134; 4,997,444; 5,002,579;
5,443,512; 5,133,762; 5,080,678; 5,944,759; 5,944,758; 5,944,757;
5,944,756; 5,938,702; 5,935,174; 5,935,175; 5,935,173; 5,935,172;
5,935,171; 5,931,871; 5,931,870; 5,928,289; 5,928,288; 5,928,287;
5,928,286; 5,928,285; 5,919,236; 5,916,270; 5,916,269; 5,916,268;
5,913,858; 5,911,759; 5,911,758; 5,910,172; 5,910,171; 5,906,644;
5,906,643; 5,906,210; 5,904,720; 5,904,688; 5,902,340; 5,882,206;
5,888,204; 5,879,407; 5,879,405; 5,879,404; 5,879,402; 5,879,401;
5,879,398; 5,879,397; 5,879,396; 5,879,395; 5,879,393; 5,879,392;
5,879,390; 5,879,387; 5,871,548; 5,871,547; 5,824,108; 5,824,107;
5,824,103; 5,824,102; 5,824,101; 5,824,098; 5,800,560; 5,800,558;
5,800,557; 5,800,555; 5,800,554; 5,800,553; 5,788,704; 5,782,928;
5,782,925; 5,776,202; 5,766,260; 5,766,257; 5,755,811; 5,755,810;
5,755,804; 5,755,801; 5,755,799; 5,743,918; 5,910,172; 5,211,666;
5,507,832; 4,433,440; 5,397,359; 5,507,834; 5,314,492; 5,405,394;
5,316,550; 5,314,494; 5,413,610; 5,507,835; 5,373,621; 5,433,750;
3,879,767; 5,376,123; 5,480,437; 3,576,133; 5,376,126; 5,496,375;
3,600,718; 5,108,449; 5,507,817; 5,181,929 and 5,507,829.
[0005] Foreign patents DE 2,247,721; EP 0,308,081; GB 2,126,096; GB
2,069,338; EP 0,190,446; EP 0,066,092 and EP 0,253,941.
SUMMARY OF THE INVENTION
[0006] The present invention seeks to provide improved joint
implants and methods relating to joint implantation.
[0007] The present invention seeks to provide improved joint
implants and methods relating to joint implantation.
[0008] There is thus provided in accordance with a preferred
embodiment of the present invention an implantable artificial
socket for a joint formed by molding of polyurethane.
[0009] There is also provided in accordance with a preferred
embodiment of the present invention a unitary implantable
artificial socket for a joint formed of a resilient material.
[0010] There is further provided in accordance with a preferred
embodiment of the present invention an implantable artificial
socket for a joint and including a one-piece resilient element
which is snap-fit engageable with a bone and which defines a wear
resistant articulation surface.
[0011] There is also provided in accordance with another preferred
embodiment of the present invention a manufacturing method for an
implantable artificial socket for a joint including forming the
socket by molding of polyurethane.
[0012] Further in accordance with a preferred embodiment of the
present invention the implantable artificial socket for a joint is
generally of uniform thickness.
[0013] Typically, the implantable artificial socket is symmetric
about an axis of rotation.
[0014] Preferably, the implantable artificial socket includes a
hemispherical concave inner articulation surface.
[0015] Preferably, the hemispherical concave inner articulation
surface has a beveled edge.
[0016] Still further in accordance with a preferred embodiment of
the present invention the implantable socket for a joint includes a
generally hemispherical outer bone engagement surface.
[0017] Additionally in accordance with a preferred embodiment of
the present invention the generally hemispherical outer bone
engagement surface has formed thereon, at a location between an
apex and a rim thereof, a generally annular outwardly extending
protrusion.
[0018] Further in accordance with a preferred embodiment of the
present invention the generally annular outwardly extending
protrusion defines a generally annular undercut.
[0019] Typically, the generally annular outwardly extending
protrusion is a generally peripheral protrusion.
[0020] Further in accordance with a preferred embodiment of the
present invention the generally annular outwardly extending
protrusion is arranged for snap-fit engagement with a corresponding
groove formed by reaming of a bone.
[0021] Still further in accordance with a preferred embodiment of
the present invention the generally annular outwardly extending
protrusion has a cross-sectional configuration, which is
characterized in that an underlying surface portion thereof, at an
undercut, defines a slope which is sharper than a corresponding
slope of an overlying surface portion thereof.
[0022] Additionally in accordance with a preferred embodiment of
the present invention the generally hemispherical outer bone
engagement surface has formed thereon, at a location between an
apex and a rim thereof, a generally annular outwardly extending
array of discrete protrusions.
[0023] Preferably, the generally annular outwardly extending array
of discrete protrusions defines a generally annular array of
undercuts.
[0024] Further in accordance with a preferred embodiment of the
present invention the generally annular outwardly extending array
of discrete protrusions defines a generally peripheral array of
protrusions.
[0025] Still further in accordance with a preferred embodiment of
the present invention the generally annular outwardly extending
array of discrete protrusions is arranged for snap-fit engagement
with corresponding grooves formed in a bone.
[0026] Preferably, each protrusion within the array of protrusions
has a cross-sectional configuration, which is characterized in that
an underlying surface portion of the protrusion, at an undercut,
defines a slope, which is sharper than a corresponding slope of an
overlying surface portion of the protrusion.
[0027] Typically, each protrusion within the array of protrusions
has a generally button-like configuration, which is symmetric about
an axis and includes a body portion and an enlarged head
portion.
[0028] Additionally or alternatively, protrusion within the array
of protrusions is generally characterized in that an underlying
surface portion of the protrusion defines a peripheral undercut
with respect to the axis.
[0029] Further in accordance with a preferred embodiment of the
present invention the generally hemispherical outer bone engagement
surface has formed thereon, at a location between an apex and a rim
thereof, a generally annular inwardly extending recess.
[0030] Still further in accordance with a preferred embodiment of
the present invention the generally annular inwardly extending
recess defines a generally annular undercut.
[0031] Typically, the generally annular inwardly extending recess
is a generally peripheral recess.
[0032] Additionally in accordance with a preferred embodiment of
the present invention the generally annular inwardly extending
recess is arranged for snap-fit engagement with a corresponding
protrusion formed in a bone.
[0033] Moreover in accordance with a preferred embodiment of the
present invention the generally annular inwardly extending recess
has a cross-sectional configuration which is characterized in that
an underlying surface portion thereof, at an undercut, defines a
slope, which is sharper than a corresponding slope of an overlying
surface portion thereof.
[0034] Further in accordance with a preferred embodiment of the
present invention the generally hemispherical outer bone engagement
surface has formed thereon, at a location between an apex and a rim
thereof, a generally annular inwardly extending array of discrete
recesses.
[0035] Still further in accordance with a preferred embodiment of
the present invention the generally annular inwardly extending
array of discrete recesses defines a generally annular array of
undercuts.
[0036] Additionally in accordance with a preferred embodiment of
the present invention the generally annular inwardly extending
array of discrete recesses defines a generally peripheral array of
recesses.
[0037] Typically, the generally annular inwardly extending array of
discrete recesses is arranged for snap-fit engagement with
corresponding protrusions formed in a bone.
[0038] Further in accordance with a preferred embodiment of the
present invention each recess of the array of recesses has a
cross-sectional configuration, which is characterized in that an
underlying surface portion of the recess, at an undercut, defines a
slope which is sharper than a corresponding slope of an overlying
surface portion of the recess.
[0039] Additionally in accordance with a preferred embodiment of
the present invention each recess of the array of recesses has a
generally button-like configuration, which is symmetric about an
axis and includes a body portion and an enlarged head portion.
[0040] Still further in accordance with a preferred embodiment of
the present invention each recess of the array of recesses is
generally characterized in that an underlying surface portion of
the recess defines a peripheral undercut with respect to the
axis.
[0041] There is also provided in accordance with a preferred
embodiment of the present invention an implantable artificial
femoral head resurfacing element for a joint formed by molding of
polyurethane.
[0042] There is further provided in accordance with yet another
preferred embodiment of the present invention a manufacturing
method for an implantable artificial humeral head resurfacing
element for a joint. The method includes forming the resurfacing
element by molding of polyurethane.
[0043] Further in accordance with a preferred embodiment of the
present invention the implantable artificial femoral head
resurfacing element for a joint is generally of uniform thickness
other than at its apex, which is thickened.
[0044] Typically, the implantable artificial femoral head
resurfacing element for a joint is symmetric about an axis of
rotation.
[0045] Still further in accordance with a preferred embodiment of
the present invention the implantable artificial femoral head
resurfacing element for a joint includes a hemispherical outer
articulation surface.
[0046] Typically, the hemispherical outer articulation surface has
a beveled edge.
[0047] Further in accordance with a preferred embodiment of the
present invention the implantable artificial femoral head
resurfacing element for a joint includes a generally hemispherical
inner bone engagement surface.
[0048] Typically, the generally hemispherical inner bone engagement
surface has formed thereon, at a location between an apex and a rim
thereof, a generally annular inwardly extending protrusion.
[0049] Further in accordance with a preferred embodiment of the
present invention the generally annular inwardly extending
protrusion defines a generally annular undercut.
[0050] Still further in accordance with a preferred embodiment of
the present invention the generally annular inwardly extending
protrusion is a generally peripheral protrusion.
[0051] Additionally in accordance with a preferred embodiment of
the present invention the generally annular inwardly extending
protrusion is arranged for snap-fit engagement with a corresponding
groove formed by reaming of a bone.
[0052] Typically, the generally annular inwardly extending
protrusion has a cross-sectional configuration, which is
characterized in that an underlying surface portion thereof at an
undercut defines a slope, which is sharper than a corresponding
slope of an overlying surface portion thereof.
[0053] Further in accordance with a preferred embodiment of the
present invention the generally hemispherical inner bone engagement
surface has formed thereon, at a location between an apex and a rim
thereof, a generally annular inwardly extending array of discrete
protrusions.
[0054] Additionally in accordance with a preferred embodiment of
the present invention the generally annular inwardly extending
array of discrete protrusions defines a generally annular array of
undercuts.
[0055] Additionally or alternatively, the generally annular
inwardly extending array of discrete protrusions defines a
generally peripheral array of protrusions.
[0056] Typically, the generally annular inwardly extending array of
discrete protrusions is arranged for snap-fit engagement with
corresponding grooves formed in a bone.
[0057] Further in accordance with a preferred embodiment of the
present invention each protrusion within the array of protrusions
has a cross-sectional configuration, which is characterized in that
an underlying surface portion of the protrusion, at an undercut,
defines a slope which is sharper than a corresponding slope of an
overlying surface portion of the protrusion.
[0058] Typically, each protrusion within the array of protrusions
has a generally button-like configuration, which is symmetric about
an axis and includes a body portion and an enlarged head
portion.
[0059] Typically, each protrusion within the array of protrusions
is generally characterized in that an underlying surface portion of
the protrusion defines a peripheral undercut with respect to the
axis.
[0060] Further in accordance with a preferred embodiment of the
present invention the generally hemispherical inner bone engagement
surface has formed thereon, at a location between an apex and a rim
thereof, a generally annular outwardly extending recess.
[0061] Still further in accordance with a preferred embodiment of
the present invention the generally annular outwardly extending
recess defines a generally annular undercut.
[0062] Typically, the generally annular outwardly extending recess
is a generally peripheral recess.
[0063] Additionally in accordance with a preferred embodiment of
the present invention the generally annular outwardly extending
recess is arranged for snap-fit engagement with a corresponding
protrusion formed in a bone.
[0064] Further in accordance with a preferred embodiment of the
present invention the generally annular outwardly extending recess
has a cross-sectional configuration, which is characterized in that
an underlying surface portion thereof at an undercut defines a
slope, which is sharper than a corresponding slope of an overlying
surface portion thereof.
[0065] Still further in accordance with a preferred embodiment of
the present invention the generally hemispherical inner bone
engagement surface has formed thereon, at a location between an
apex and a rim thereof, a generally annular outwardly extending
array of discrete recesses.
[0066] Typically, the generally annular outwardly extending array
of discrete recesses defines a generally annular array of
undercuts.
[0067] Additionally or alternatively, the generally annular
outwardly extending array of discrete recesses defines a generally
peripheral array of recesses.
[0068] Further in accordance with a preferred embodiment of the
present invention the generally annular outwardly extending array
of discrete recesses is arranged for snap-fit engagement with
corresponding protrusions formed in a bone.
[0069] Still further in accordance with a preferred embodiment of
the present invention each recess in the array of recesses has a
cross-sectional configuration, which is characterized in that an
underlying surface portion of the recess, at an undercut, defines a
slope which is sharper than a corresponding slope of an overlying
surface portion of the recess.
[0070] Typically, each recess within the array of recesses has a
generally button-like configuration, which is symmetric about an
axis and includes a body portion and an enlarged head portion.
[0071] Preferably, each recess within the array of recesses is
generally characterized in that an underlying surface portion of
the recess defines a peripheral undercut with respect to the
axis.
[0072] Further in accordance with a preferred embodiment of the
present invention the implantable artificial socket is typically
snap-fitted into a suitably machined natural acetabulum of a
patient and having an artificial femoral head mounted onto a
conventional femoral stem and arranged for articulation with an
articulation surface of the socket.
[0073] Still further in accordance with a preferred embodiment of
the present invention the implantable artificial socket is
typically snap-fitted into a suitably machined natural acetabulum
of a patient and having a natural femoral head arranged for
articulation with an articulation surface of the socket.
[0074] Additionally in accordance with a preferred embodiment of
the present invention the size and configuration of an articulation
surface of the socket is identical to that of the natural
acetabulum socket of the patient, in order that a natural femoral
head may articulate therewith with desired dimensional clearances
and without requiring machining of the femoral head.
[0075] Further in accordance with a preferred embodiment of the
present invention the implantable artificial socket is typically
snap-fitted into a suitably machined natural acetabulum of a
patient and having a natural femoral head having an implantable
artificial femoral head resurfacing element and is preferably
snap-fit mounted thereon arranged for articulation of an
articulation surface thereof with an articulation surface of the
socket.
[0076] Typically, the implantable artificial femoral head
resurfacing element is snap-fit mounted onto a natural femoral head
and arranged for articulation of an articulation surface thereof
with a natural articulation surface of a natural acetabulum.
[0077] Further in accordance with a preferred embodiment of the
present invention the implantable artificial femoral head
resurfacing element is snap-fit mounted onto a natural femoral head
and arranged for articulation of an articulation surface thereof
with a natural acetabulum socket of a patient, wherein the size and
configuration of an articulation surface of the artificial femoral
head resurfacing element is identical to that of the natural
acetabulum socket of the patient, in order that the natural femoral
head onto which artificial femoral head resurfacing element is
mounted may articulate therewith with desired dimensional
clearances and without requiring machining of the natural
acetabulum.
[0078] Preferably, the implantable artificial socket for a joint
includes a spherical concave inner articulation surface.
[0079] Typically, the spherical concave inner articulation surface
has a beveled edge.
[0080] Further in accordance with a preferred embodiment of the
present invention the implantable artificial socket for a joint
includes an outer bone engagement surface
[0081] Preferably, the outer bone engagement surface has multiple
protrusions formed thereon.
[0082] Further in accordance with a preferred embodiment of the
present invention the multiple protrusions include inner and outer
protrusions.
[0083] Preferably, the multiple protrusions include undercuts.
[0084] Still further in accordance with a preferred embodiment of
the present invention the multiple protrusions are arranged for
snap-fit engagement with a corresponding groove formed in a
bone.
[0085] Additionally in accordance with a preferred embodiment of
the present invention the multiple protrusions include a
cross-sectional configuration which is characterized in that an
underlying surface portion thereof at an undercut defines a slope,
which is sharper than a corresponding slope of an overlying surface
portion thereof.
[0086] Typically, the multiple protrusions include an array of
outwardly extending discrete protrusions.
[0087] Further in accordance with a preferred embodiment of the
present invention the array of discrete protrusions defines an
array of undercuts.
[0088] Typically, the array of discrete protrusions includes a
generally peripheral array of protrusions.
[0089] Still further in accordance with a preferred embodiment of
the present invention the array of discrete protrusions is arranged
for snap-fit engagement with corresponding grooves formed in a
bone.
[0090] Additionally in accordance with a preferred embodiment of
the present invention each protrusion within the array of
protrusions has a cross-sectional configuration, which is
characterized in that an underlying surface portion of the
protrusion, at an undercut, defines a slope which is sharper than a
corresponding slope of an overlying surface portion of the
protrusion.
[0091] Typically, each protrusion within the array of protrusions
has a generally button-like configuration, which is symmetric about
an axis and includes a body portion and an enlarged head
portion.
[0092] Further in accordance with a preferred embodiment of the
present invention the protrusion within the array of protrusions is
generally characterized in that an underlying surface portion of
the protrusion defines a peripheral undercut with respect to the
axis.
[0093] Still further in accordance with a preferred embodiment of
the present invention the outer bone engagement surface has
multiple recesses formed thereon.
[0094] Typically, the multiple recesses include undercuts.
[0095] Further in accordance with a preferred embodiment of the
present invention the multiple recesses include an inner recess and
outer protrusions.
[0096] Typically, the multiple recesses are arranged for snap-fit
engagement with corresponding protrusions formed in a bone.
[0097] Further in accordance with a preferred embodiment of the
present invention the multiple recesses has a cross-sectional
configuration which is characterized in that an underlying surface
portion thereof at an undercut defines a slope which is sharper
than a corresponding slope of an overlying surface portion
thereof.
[0098] Additionally in accordance with a preferred embodiment of
the present invention the outer bone engagement surface has formed
thereon an inwardly extending array of discrete recesses.
[0099] Typically, the array of discrete recesses includes an array
of undercuts.
[0100] Further in accordance with a preferred embodiment of the
present invention the array of discrete recesses includes a
generally peripheral array of recesses.
[0101] Still further in accordance with a preferred embodiment of
the present invention the array of discrete recesses is arranged
for snap-fit engagement with corresponding protrusions formed in a
bone.
[0102] Additionally in accordance with a preferred embodiment of
the present invention each recess within the array of recesses has
a cross-sectional configuration which is characterized in that an
underlying surface portion of each recess, at an undercut, defines
a slope which is sharper than a corresponding slope of an overlying
surface portion of the recess.
[0103] Typically, each recess within the array of recesses has a
generally button-like configuration, which is symmetric about an
axis and includes a body portion and an enlarged head portion.
[0104] Further in accordance with a preferred embodiment of the
present invention each recess within the array of recesses is
generally characterized in that an underlying surface portion of
the recess defines a peripheral undercut with respect to the
axis.
[0105] There is further provided in accordance with a preferred
embodiment of the present invention an implantable artificial
humeral head resurfacing element for a joint formed by molding of
polyurethane.
[0106] There is further provided in accordance with yet another
preferred embodiment of the present invention a manufacturing
method for an implantable artificial femoral head resurfacing
element for a joint. The method includes forming the resurfacing
element by molding of polyurethane.
[0107] Further in accordance with a preferred embodiment of the
present invention the implantable artificial humeral head
resurfacing element for a joint is generally of uniform thickness
other than at its apex, which is thickened.
[0108] Still further in accordance with a preferred embodiment of
the present invention the implantable artificial humeral head
resurfacing element for a joint is symmetric about an axis of
rotation.
[0109] Additionally in accordance with a preferred embodiment of
the present invention the implantable artificial humeral head
resurfacing element for a joint includes a convex spherical outer
articulation surface.
[0110] Typically, the convex spherical outer articulation surface
has a beveled edge.
[0111] Further in accordance with a preferred embodiment of the
present invention the implantable artificial humeral head
resurfacing element for a joint includes a generally convex
spherical inner bone engagement surface.
[0112] Typically, the generally convex spherical inner bone
engagement surface has formed thereon, at a location between an
apex and a rim thereof, a generally annular inwardly extending
protrusion.
[0113] Additionally in accordance with a preferred embodiment of
the present invention the generally annular inwardly extending
protrusion defines a generally annular undercut.
[0114] Preferably, the generally annular inwardly extending
protrusion is a generally peripheral protrusion.
[0115] Further in accordance with a preferred embodiment of the
present invention the generally annular inwardly extending
protrusion is arranged for snap-fit engagement with a corresponding
groove formed by reaming of a bone.
[0116] Further in accordance with a preferred embodiment of the
present invention the generally annular inwardly extending
protrusion has a cross-sectional configuration, which is
characterized in that an underlying surface portion thereof at an
undercut defines a slope, which is sharper than a corresponding
slope of an overlying surface portion thereof.
[0117] Further in accordance with a preferred embodiment of the
present invention the generally convex spherical inner bone
engagement surface has formed thereon, at a location between an
apex and a rim thereof, a generally annular inwardly extending
array of discrete protrusions.
[0118] Preferably, the generally annular inwardly extending array
of discrete protrusions defines a generally annular array of
undercuts.
[0119] Additionally or alternatively, the generally annular
inwardly extending array of discrete protrusions includes a
generally peripheral array of protrusions.
[0120] Still further in accordance with a preferred embodiment of
the present invention the generally annular inwardly extending
array of discrete protrusions is arranged for snap-fit engagement
with corresponding grooves formed in a bone.
[0121] Further in accordance with a preferred embodiment of the
present invention each protrusion within the array of protrusions
has a cross-sectional configuration, which is characterized in that
an underlying surface portion of the protrusion, at an undercut,
defines a slope which is sharper than a corresponding slope of an
overlying surface portion of the protrusion.
[0122] Typically, each protrusion within the array of protrusions
has a generally button-like configuration, which is symmetric about
an axis and includes a body portion and an enlarged head
portion.
[0123] Still further in accordance with a preferred embodiment of
the present invention each protrusion within the array of
protrusions is generally characterized in that an underlying
surface portion of the protrusion defines a peripheral undercut
with respect to the axis.
[0124] Additionally in accordance with a preferred embodiment of
the present invention the generally convex spherical inner bone
engagement surface includes thereon, at a location between an apex
and a rim thereof, a generally annular outwardly extending
recess.
[0125] Further in accordance with a preferred embodiment of the
present invention the generally annular outwardly extending recess
defines a generally annular undercut.
[0126] Typically, the generally annular outwardly extending recess
is a generally peripheral recess.
[0127] Further in accordance with a preferred embodiment of the
present invention the generally annular outwardly extending recess
is arranged for snap-fit engagement with a corresponding protrusion
formed in a bone.
[0128] Still further in accordance with a preferred embodiment of
the present invention the generally annular outwardly extending
recess has a cross-sectional configuration, which is characterized
in that an underlying surface portion thereof at an undercut
defines a slope, which is sharper than a corresponding slope of an
overlying surface portion thereof.
[0129] Further in accordance with a preferred embodiment of the
present invention the generally convex spherical inner bone
engagement surface has formed thereon, at a location between an
apex and a rim thereof, a generally annular outwardly extending
array of discrete recesses.
[0130] Preferably, the generally annular outwardly extending array
of discrete recesses defines a generally annular array of
undercuts.
[0131] Typically, the generally annular outwardly extending array
of discrete recesses defines a generally peripheral array of
recesses.
[0132] Additionally in accordance with a preferred embodiment of
the present invention the generally annular outwardly extending
array of discrete recesses is arranged for snap-fit engagement with
corresponding protrusions formed in a bone.
[0133] Typically, each recess within the array of recesses has a
cross-sectional configuration, which is characterized in that an
underlying surface portion of each recess, it an undercut, defines
a slope, which is sharper than a corresponding slope of an
overlying surface portion of the recess.
[0134] Further in accordance with a preferred embodiment of the
present invention each recess within the array of recesses has a
generally button-like configuration, which is symmetric about an
axis and includes a body portion and an enlarged head portion.
[0135] Still further in accordance with a preferred embodiment of
the present invention each recess within the array of recesses is
generally characterized in that an underlying surface portion of
each recess defines a peripheral undercut with respect to the
axis.
[0136] Additionally in accordance with a preferred embodiment of
the present invention the implantable artificial socket according
is snap-fitted into a suitably machined natural glenoid of a
patient and having an artificial humeral head mounted onto a
conventional humeral stem and arranged for articulation with an
articulation surface of the socket.
[0137] Still further in accordance with a preferred embodiment of
the present invention the implantable artificial socket is
snap-fitted into a suitably machined natural glenoid of a patient
and having a natural humeral head arranged for articulation with an
articulation surface of the socket.
[0138] Typically, the size and configuration of an articulation
surface of the socket is identical to that of the natural glenoid
socket of the patient, in order that a natural humeral head may
articulate therewith with desired dimensional clearances and
without requiring machining of the humeral head.
[0139] Additionally in accordance with a preferred embodiment of
the present invention the implantable artificial socket is
snap-fitted into a suitably machined natural glenoid of a patient
and having a natural humeral head having an implantable artificial
humeral head resurfacing element and is typically snap-fit mounted
thereon arranged for articulation of an articulation surface
thereof with an articulation surface of the socket.
[0140] Further in accordance with a preferred embodiment of the
present invention the implantable artificial humeral head
resurfacing element is snap-fit mounted onto a natural humeral head
and arranged for articulation of an articulation surface thereof
with a natural articulation surface of a natural glenoid.
[0141] Still further in accordance with a preferred embodiment of
the present invention the implantable artificial humeral head
resurfacing element is snap-fit mounted onto a natural humeral head
and arranged for articulation of an articulation surface thereof
with a natural glenoid socket of a patient, wherein the size and
configuration of an articulation surface of the artificial humeral
head resurfacing element is identical to that of the natural
glenoid socket of the patient, in order that the natural humeral
head onto which artificial humeral head resurfacing element is
mounted may articulate therewith with desired dimensional
clearances and without requiring machining of the natural
glenoid.
[0142] Preferably, the articulation portion is formed with a highly
resilient hollow peripheral rim arranged for snap-fit engagement
with a corresponding peripheral socket formed in a surface of the
bone engagement portion, opposite to the bone engagement
surface.
[0143] Additionally in accordance with a preferred embodiment of
the present invention the articulation portion is formed with a
support protrusion, defining an undercut and arranged for resilient
snap-fit locking engagement with a corresponding groove formed in
the bone engagement portion.
[0144] Further in accordance with a preferred embodiment of the
present invention the articulation surface has formed therein a
plurality of thoroughgoing apertures and side openings, which allow
synovial fluid to pass therethrough for lubrication of the
articulation surface.
[0145] Still further in accordance with a preferred embodiment of
the present invention the implantable artificial socket for a joint
is mounted onto a tibia and arranged such that application of force
to the joint causes the articulation portion to be resiliently
displaced toward the bone engagement portion, thus causing synovial
fluid, located between the articulation portion and the bone
engagement portion, to be forced through apertures and openings so
as to lie on and over the articulation surface and to provide
enhanced lubrication for the articulation of an articulation
surface of a femur with the articulation surface.
[0146] Typically, the application of force causes the movement of
the articulation portion by resilient buckling of at least one
protrusion and compression of a resilient rim and release of the
force causes movement of articulation portion, accompanied by
resilient return of the protrusion to its unstressed orientation
and decompression of the resilient rim, wherein the application of
force does not cause significant deformation of the geometry of the
articulation surface.
[0147] There is also provided in accordance with another preferred
embodiment of the present invention a method for implanting an
implantable artificial socket. The method for implanting an
implantable artificial socket includes providing an implantable
artificial socket, suitably machining a natural acetabulum of a
patient to fit the implantable artificial socket, snap-fitting the
implantable artificial socket onto the natural acetabulum, mounting
an artificial femoral head onto a conventional femoral stem and
arranging the femoral head for articulation with an articulation
surface of the implantable artificial socket.
[0148] There is further provided in accordance with yet another
preferred embodiment of the present invention a method for
implanting an implantable artificial socket. The method includes
providing an implantable artificial socket, suitably machining a
natural acetabulum of a patient to fit the implantable artificial
socket, snap-fitting the implantable artificial socket onto the
natural acetabulum and arranging a natural femoral head for
articulation with an articulation surface of the implantable
artificial socket.
[0149] Further in accordance with a preferred embodiment of the
present invention the method for implanting an implantable
artificial socket also includes matching the size and configuration
of an articulation surface of the socket to that of the natural
acetabulum socket of the patient and arranging a natural femoral
head for articulation therewith, the matching providing desired
dimensional clearances without requiring machining of the femoral
head.
[0150] There is provided in accordance with still a further
embodiment of the present invention a method for implanting an
implantable artificial socket. The method includes providing an
implantable artificial socket, suitably machining a natural
acetabulum of a patient to fit the implantable artificial socket,
snap-fitting the implantable artificial socket onto the natural
acetabulum, snap-fit mounting an implantable artificial femoral
head resurfacing element onto a natural femoral head and arranging
an articulation surface of the femoral head for articulation with
an articulation surface of the implantable artificial socket.
[0151] There is also provided in accordance with another preferred
embodiment of the present invention a method for implanting an
implantable artificial femoral head resurfacing element. The method
includes providing an implantable artificial femoral head
resurfacing element, snap-fit mounting the artificial femoral head
resurfacing element onto a natural femoral head and arranging an
articulation surface of the artificial femoral head resurfacing
element for articulation with a natural articulation surface of a
natural acetabulum.
[0152] Still further in accordance with a preferred embodiment of
the present invention the method also includes matching the size
and configuration of an articulation surface of the artificial
femoral head resurfacing element to that of the natural acetabulum
socket of the patient, the matching providing for the natural
femoral head onto which the artificial femoral head resurfacing
element is mounted to articulate with the natural acetabulum socket
with desired dimensional clearances without requiring machining of
the natural acetabulum.
[0153] There is also provided in accordance with a preferred
embodiment of the present invention a method for implanting an
implantable artificial socket, which includes providing an
implantable artificial socket, suitably machining a natural glenoid
of a patient to fit the implantable artificial socket, snap-fitting
the implantable artificial socket into the natural glenoid,
mounting an artificial humeral head onto a conventional humeral
stem and arranging the humeral head for articulation with an
articulation surface of the implantable artificial socket.
[0154] There is further provided in accordance with another
preferred embodiment of the present invention a method for
implanting an implantable artificial socket, which includes
providing an implantable artificial socket, suitably machining a
natural glenoid of a patient to fit the implantable artificial
socket, snap-fitting the implantable artificial socket into the
natural glenoid and arranging a natural humeral head for
articulation with an articulation surface of the implantable
artificial socket
[0155] Further in accordance with a preferred embodiment of the
present invention the method for implanting an implantable
artificial socket also includes matching the size and configuration
of an articulation surface of the socket to that of the natural
glenoid socket of the patient and arranging a natural humeral head
for articulation therewith, the matching providing desired
dimensional clearances without requiring machining of the humeral
head.
[0156] There is also provided in accordance with a further
preferred embodiment of the present invention a method for
implanting an implantable artificial socket The method includes
providing an implantable artificial socket, suitably machining a
natural glenoid of a patient to fit the implantable artificial
socket, snap-fitting the implantable artificial socket onto the
natural glenoid, snap-fit mounting an implantable artificial
humeral head resurfacing element onto a natural humeral head and
arranging an articulation surface of the humeral head for
articulation with an articulation surface of the implantable
artificial socket.
[0157] There is further provided in accordance with yet another
preferred embodiment of the present invention a method for
implanting an implantable artificial humeral head resurfacing
element. The method includes providing an implantable artificial
humeral head resurfacing element, snap-fit mounting the artificial
humeral head resurfacing element onto a natural humeral head and
arranging an articulation surface of the artificial humeral head
resurfacing element for articulation with a natural articulation
surface of a natural glenoid.
[0158] Further in accordance with a preferred embodiment of the
present invention the method for implanting an implantable
artificial humeral head resurfacing element also includes matching
the size and configuration of an articulation surface of the
artificial humeral head resurfacing element to that of the natural
glenoid socket of the patient, the matching providing for the
natural humeral head onto which the artificial humeral head
resurfacing element is mounted to articulate with the natural
glenoid socket with desired dimensional clearances without
requiring machining of the natural glenoid.
[0159] Further in accordance with a preferred embodiment of the
present invention the implantable artificial femoral resurfacing
element for a joint defines an articulation portion having a convex
outer articulation surface and a bone engagement portion having a
bone engagement surface.
[0160] Still further in accordance with a preferred embodiment of
the present invention the articulation portion of the artificial
socket for a joint is formed with a highly resilient hollow
peripheral rim arranged for snap-fit engagement with a
corresponding peripheral femoral resurfacing element formed in a
surface of the bone engagement portion, opposite to the bone
engagement surface.
[0161] Additionally in accordance with a preferred embodiment of
the present invention the articulation portion is formed with a
support protrusion, defining an undercut and arranged for resilient
snap-fit locking engagement with a corresponding groove formed in
the bone engagement portion.
[0162] Typically, the articulation surface has formed therein a
plurality of thoroughgoing apertures and side openings, which allow
synovial fluid to pass therethrough for lubrication of the
articulation surface.
[0163] Further in accordance with a preferred embodiment of the
present invention the implantable artificial femoral resurfacing
element for a joint is mounted onto a femur and arranged such that
application of force to the joint causes the articulation portion
to be resiliently displaced toward the bone engagement portion,
thus causing synovial fluid, located between the articulation
portion and the bone engagement portion to be forced through
apertures and openings so as to lie on and over the articulation
surface and to provide enhanced lubrication for the articulation of
an articulation surface of a femur with the articulation
surface.
[0164] Typically, the application of force causes the movement of
the articulation portion by resilient buckling of at least one
protrusion and compression of a resilient rim and release of the
force causes movement of articulation portion, accompanied by
resilient return of the protrusion to its unstressed orientation
and decompression of the resilient rim, wherein the application of
force does not cause significant deformation of the geometry of the
articulation surface.
[0165] Further in accordance with a preferred embodiment of the
present invention the implantable artificial socket is in
articulation engagement with an implantable artificial femoral
resurfacing element.
[0166] There is further provided in accordance with a preferred
embodiment of the present invention a groove reaming tool including
a shaft, a handle, fixedly coupled to the shaft, an outwardly
extendible recess engagement element, which is also rotatably and
slidably mounted with respect to the shaft and an elongate grip,
rotatably and slidably mounted over the shaft and axially engaging
the outwardly extendible recess engagement element.
[0167] Further in accordance with a preferred embodiment of the
present invention the outwardly extendible recess engagement
element is an integrally formed element and includes a generally
hollow cylindrical portion formed with a plurality of axially
extending slots, which extend from a location spaced from a top
edge of the cylindrical portion towards and through a generally
radially outwardly extending disk-like portion.
[0168] Still further in accordance with a preferred embodiment of
the present invention the disk-like portion includes a plurality of
azimuthally separated segments, each of which defines a
continuation of a corresponding azimuthally separated segment of
the cylindrical portion.
[0169] Preferably, the disk-like portion has an outer edge which is
formed with a high friction engagement surface.
[0170] Further in accordance with a preferred embodiment of the
present invention the disk-like portion is formed with a central
generally conical recess on an underside surface thereof.
[0171] Preferably, the groove reaming tool also includes a
generally solid, centrally apertured conical element, rotatably
mounted onto the shaft such that a conical surface thereof is
adapted to operative engage the conical recess in a manner that
such engagement produces radially outward displacement of the
segments of the disk-like portion.
[0172] Further in accordance with a preferred embodiment of the
present invention the groove reaming tool further includes a
retainer element which is rotatably mounted with respect to the
shaft and overlies the disk-like portion.
[0173] Additionally in accordance with a preferred embodiment of
the present invention the retainer element includes depending
plates which engage interstices between the segments.
[0174] Further in accordance with a preferred embodiment of the
present invention the groove reaming tool also includes a groove
cutter assembly.
[0175] Preferably, the groove cutter assembly includes a groove
cutter mounting element, fixedly mounted to the shaft for rotation
together therewith in response to rotation of the handle.
[0176] Further in accordance with a preferred embodiment of the
present invention the groove cutter mounting element underlies
conical element and is separated therefrom by a washer, in order to
enable the groove cutter mounting element to easily rotate with
respect to the conical element.
[0177] Still further in accordance with a preferred embodiment of
the present invention the groove reaming tool further includes an
end element, rotatably mounted onto an end of the shaft, underlying
the groove cutter mounting element such that the groove cutter
mounting element is rotatable with respect thereto.
[0178] Typically, the end element is formed with a high friction
engagement surface on the underside thereof.
[0179] Further in accordance with a preferred embodiment of the
present invention the groove cutter mounting element is a generally
hollow hemispherical element having a central hub which defines a
non-circular thoroughgoing aperture for receiving an end of the
shaft, a radially inward extending recess is formed in an outer
facing wall of the hub and a corresponding generally elongate
aperture is formed in a wall of the groove cutter mounting element
opposite the recess and extends azimuthally beyond the recess.
[0180] Additionally in accordance with a preferred embodiment of
the present invention the groove reaming tool also includes a
plurality of cutter elements, removably retained in the groove
cutter mounting element.
[0181] Preferably, the cutter elements have similar configurations
and have at least one differing dimension.
[0182] Further in accordance with a preferred embodiment of the
present invention each cutter element is formed of a flat piece of
metal and includes a hook portion, defining an undercut, a central
portion and a cutting portion, which defines a curved cutting
edge.
[0183] Preferably, the cutting portion defines, inwardly of the
curved cutting edge, an aperture having a beveled peripheral
edge.
[0184] Further in accordance with a preferred embodiment of the
present invention the cutter elements are arranged such that their
hook portions engage the recess and the cutting portions extend
outwardly through the aperture.
[0185] Still further in accordance with a preferred embodiment of
the present invention the cutter elements are arranged to provide a
stepped increase in the extent that the cutting portions extend
outwardly, in the direction of operational rotation of the tool
[0186] Additionally in accordance with a preferred embodiment of
the present invention the tool has first and second operative
orientations, the first operative orientation being a
non-engagement orientation, when the grip is not pushed along the
shaft towards the groove cutter mounting element and the outwardly
extendible recess engagement element is not subject to axial force
and thus no axial force is applied between the recess on the
underside surface thereof and the conical element.
[0187] Preferably, in the second operative orientation is bone
recess engagement orientation wherein the grip is pushed along the
shaft towards the groove cutter mounting element and engages the
outwardly extendible recess engagement element, forcing the recess
on the underside surface thereof axially against the conical
element and causing radially outward displacement of the segments
of the disk-like portion.
[0188] Further in accordance with a preferred embodiment of the
present invention a method of groove reaming of an acetabulum
including engaging a groove reaming tool with an acetabulum which
has been at least partially spherically reamed by aligning the
cutting portions of the cutting elements with an acetabulum notch
and arranging the shaft along an axis which is approximately
coaxial with an axis of symmetry of the at least partially
spherically reamed acetabulum.
[0189] Still further in accordance with a preferred embodiment of
the present invention the method also includes applying an axial
force on the handle, thereby causing the high friction engagement
surface of the end element to frictionally engage the at least
partially spherically reamed acetabulum.
[0190] Additionally in accordance with a preferred embodiment of
the present invention the method further includes applying an axial
force on the grip, causing the grip to engage the outwardly
extendible recess engagement element and to force the recess on the
underside surface thereof axially against the conical element,
thereby causing radially outward displacement of the segments into
frictional engagement with the at least partially spherically
reamed acetabulum.
[0191] Further in accordance with a preferred embodiment of the
present invention the method also includes rotating the handle
through an approximately 180 degree rotation thereby producing
corresponding rotation of the groove cutter mounting element and
the cutter elements and thereby producing an approximately 180
degree groove in the at least partially spherically reamed
acetabulum.
[0192] Additionally in accordance with a preferred embodiment of
the present invention the method includes rotating the handle
through a further approximately 180 degree rotation thereby
producing corresponding rotation of the groove cutter mounting
element and the cutter elements and thereby producing an
approximately 180 degree groove in the at least partially
spherically reamed acetabulum.
[0193] There is further provided in accordance with a preferred
embodiment of the present invention a method for implanting an
artificial acetabulum socket in a hip joint, which includes at
least partially reaming of a natural acetabulum to provide a
snap-fit configured natural acetabulum and resiliently bending an
artificial acetabulum socket, so as to provide a bent acetabulum
socket having a reduced minimum cross-sectional area, inserting the
bent acetabulum socket having a reduced minimum cross-sectional
area into the vicinity of the hip joint by a minimally invasive
surgical technique and snap fitting the artificial acetabulum
socket in the snap-fit configured natural acetabulum.
[0194] There is also provided in accordance with a preferred
embodiment of the present invention a method for implanting an
artificial acetabulum socket in a hip joint. The method includes at
least partially reaming of a natural acetabulum to provide a
snap-fit configured natural acetabulum and inserting a unitary
resilient acetabulum socket into the vicinity of the hip joint and
snap fitting the artificial acetabulum socket in the snap-fit
configures natural acetabulum.
[0195] Further in accordance with a preferred embodiment of the
present invention the snap-fit configured natural acetabulum
includes a generally spherical portion and a generally cylindrical
portion.
[0196] Still further in accordance with a preferred embodiment of
the present invention the snap-fit configured natural acetabulum
defines a recessed rim.
[0197] Additionally in accordance with a preferred embodiment of
the present invention the snap-fit configured natural acetabulum is
naturally formed with a recess which extends deeper than the
remainder of the generally spherical surface.
[0198] Preferably, the snap fitting the artificial acetabulum
socket in the snap-fit configured natural acetabulum includes
gently positioning the artificial acetabulum socket into a position
for snap-fit engagement with the reamed acetabulum.
[0199] Further in accordance with a preferred embodiment of the
present invention that during the gently positioning an outwardly
extending protrusion of the artificial acetabulum socket lies in
touching, generally non-compressive engagement with an annular
portion of a generally spherical inner concave machined surface the
acetabulum, the annular portion lying above a groove, formed in the
generally spherical inner concave surface, which is designed to
receive the protrusion.
[0200] Still further in accordance with a preferred embodiment of
the present invention that during the gently positioning the
engagement of the protrusion with the annular portion causes the
implantable artificial acetabulum socket to rest at a position
wherein an outer edge thereof lies above a corresponding outer edge
of the acetabulum.
[0201] Further in accordance with a preferred embodiment of the
present invention that during the gently positioning, substantially
no stress is applied to the implantable artificial acetabulum
socket and to the acetabulum by the engagement thereof.
[0202] Additionally in accordance with a preferred embodiment of
the present invention the method also includes, following the
gently positioning, gently engaging the artificial acetabulum
socket at locations on an inner concave surface thereof and
pressing thereon in a direction generally along an axis of symmetry
of the snap-fit configured natural acetabulum, thereby causing
displacement of the artificial acetabulum socket, which produces
radially inward compression of the artificial acetabulum socket at
the protrusion and thereby resulting in deformation of the
artificial acetabulum socket at the protrusion and in the general
region thereof.
[0203] Further in accordance with a preferred embodiment of the
present invention the radially inward compression and the resulting
deformation of the artificial acetabulum socket produce stresses in
the acetabulum socket and causes forces to be applied to the
acetabulum, producing compression stresses and strains therein.
[0204] Additionally in accordance with a preferred embodiment of
the present invention the displacement of the artificial acetabulum
socket reduces the separation between the planes of the outer edge
of the implantable artificial acetabulum socket and the outer edge
of the acetabulum.
[0205] Still further in accordance with a preferred embodiment of
the present invention the method includes, following the gently
engaging, pressing further on the artificial acetabulum socket at
locations on an inner concave surface thereof, thereby causing
further displacement of the artificial acetabulum socket producing
sliding pressure engagement between an underlying surface portion
of the protrusion at the undercut and a radially outward extending
surface portion of the groove, wherein resiliency of the artificial
acetabulum socket causes radially outward displacement of the
protrusion and corresponding radially outward decompression of the
artificial acetabulum socket, resulting in reduced and changed
stress patterns in both the artificial acetabulum socket and in the
acetabulum.
[0206] Further in accordance with a preferred embodiment of the
present invention the displacement of the artificial acetabulum
socket further reduces the separation between the planes of the
outer edge of the implantable artificial acetabulum socket and the
outer edge of the acetabulum.
[0207] Further in accordance with a preferred embodiment of the
present invention the method further includes, following the
pressing further, pressing on the artificial acetabulum socket at
locations on edges thereof, thereby causing further displacement of
the artificial acetabulum socket and producing sliding snap-fit
engagement between the protrusion and the groove, wherein the
resiliency of the artificial acetabulum socket causes radially
outward displacement of the protrusion, thereby generally
eliminating deformation of the artificial acetabulum socket at the
protrusion and in the general region thereof.
[0208] Preferably, the snap fitting provides a generally non-press
fit engagement, wherein touching engagement between the artificial
acetabulum socket and the acetabulum produces stresses in both the
acetabulum socket and in the acetabulum which are generally small
and localized in the region of the snap fit engagement
therebetween.
[0209] Further in accordance with a preferred embodiment of the
present invention the snap fitting produces locking of the
artificial acetabulum socket in the groove and the undercut
prevents disengagement of the protrusion from the groove.
[0210] Additionally in accordance with a preferred embodiment of
the present invention the snap fitting provides a generally press
fit engagement, wherein touching engagement between the artificial
acetabulum socket and the acetabulum produces stresses in both the
acetabulum socket and in the acetabulum which are not localized in
the region of the snap fit engagement therebetween.
[0211] Further in accordance with a preferred embodiment of the
present invention the snap fitting in a generally press fit
engagement produces pressure engagement between the acetabulum and
a convex facing surface of the artificial acetabulum socket
generally along the entire extent thereof.
[0212] There is also provided in accordance with a preferred
embodiment of the present invention an artificial femoral head
prosthesis for use with a natural femoral head and including a
flexible bone interface element including a unitary element molded
of a single material and having an inner concave surface which is
configured to directly contact the natural femoral head in
generally static engagement therewith and a smooth outer convex
surface which is configured to be directly contacted by an
acetabulum socket in moveable engagement therewith, the flexible
bone interface element being formed of material which is more
flexible than bone material of the natural femoral head.
[0213] There is also provided in accordance with a preferred
embodiment of the present invention an artificial femoral head
prosthesis for use with a natural femoral head and including a
flexible bone interface element configured to be mounted onto the
natural femoral head, the flexible bone interface element including
a unitary element molded of a single material and having an inner
concave surface which is configured to directly contact the natural
femoral head in generally static engagement therewith, and a smooth
outer convex surface which is configured to be directly contacted
by an acetabulum socket in moveable engagement therewith, the
flexible bone interface element being formed of material which is
more flexible than bone material of particularly configured for
retainable snap-fit engagement with a suitably machine-shaped
surface of the natural femoral head.
[0214] There is also provided in accordance with a preferred
embodiment of the present invention an artificial femoral head
prosthesis for use with a natural femoral head and including a bone
interface element configured to be mounted onto the natural femoral
head, the bone interface element having an inner concave surface
which is configured to directly contact the natural femoral head in
generally static engagement therewith, the bone interface element
being particularly configured for retainable snap-fit engagement
with a suitably machine-shaped surface of the natural femoral head
and a press-fit acetabulum engagement element being particularly
configured for retainable press-fit engagement with the bone
interface element and having a smooth outer convex surface which is
configured to be directly contacted by an acetabulum socket in
moveable engagement therewith.
[0215] There is also provided in accordance with yet another
preferred embodiment of the present invention an artificial femoral
head prosthesis for use with a natural femoral head and including a
bone interface element configured to be mounted onto the natural
femoral head, the bone interface element having an inner concave
surface which is configured to directly contact the natural femoral
head in generally static engagement therewith, the bone interface
element being particularly configured for retainable snap-fit
engagement with a suitably machine-shaped surface of the natural
femoral head and a snap-fit acetabulum engagement element being
particularly configured for retainable snap-fit engagement with the
bone interface element and having a smooth outer convex surface
which is configured to be directly contacted by an acetabulum
socket in moveable engagement therewith.
[0216] There is also provided in accordance with a preferred
embodiment of the present invention a prosthesis for use with a
natural bone and including a flexible bone interface element
configured to be mounted onto the natural bone, the flexible bone
interface element including a unitary element molded of a single
material and having a contact surface which is configured to
directly contact the natural bone in generally static engagement
therewith, and wherein the contact surface is configured with a
configuration-pattern including of bone contact surface portions
defined by channels surrounding the bone contact surface portions,
and wherein the channels have a bottom surface and walls surfaces.
The flexible bone interface element being formed of material, which
is more flexible than bone material of the natural bone.
[0217] There is further provided in accordance with a preferred
embodiment of the present invention A prosthesis for use with a
natural bone and including a flexible bone interface element
configured to be mounted onto the natural bone, the flexible bone
interface element including a unitary element molded of a single
material and having a contact surface which is configured to
directly contact the natural bone in generally static engagement
therewith, and wherein the contact surface is configured with a
configuration-pattern including of surface recess portions defined
by bone contact ridges surrounding the surface recess portions, and
wherein the surface recess portions have a bottom surface and walls
surfaces. The flexible bone interface element being formed of
material, which is more flexible than bone material of the natural
bone.
[0218] Further in accordance with a preferred embodiment of the
present invention the configuration-pattern of the contact surface
is of a fractal design including of bone contact surface portions
defined by channels surrounding bone contact surface portions.
[0219] Preferably, the contact surface is convex. Alternatively or
additionally, the contact surface is concave.
[0220] Still further in accordance with a preferred embodiment of
the present invention the wall surfaces of channels are inclined
inwardly creating an undercut section with a wider lower dimension
and an narrower upper dimension.
[0221] Additionally in accordance with a preferred embodiment of
the present invention the prosthesis (convex) includes a
configuration-pattern of the bone contact surface portions is of an
hexagonal geometry.
[0222] Further in accordance with a preferred embodiment of the
present invention the configuration-pattern of the bone contact
surface portions is of a spiral geometry defined by spiral
channels.
[0223] Preferably, spiral bone contact surface portions are of a
multiple entry spiral type.
[0224] Additionally or alternatively, the configuration-pattern of
the bone contact surface portions is of a wavy geometry (tire like
treads).
[0225] Further in accordance with a preferred embodiment of the
present invention the configuration-pattern of the bone contact
surface portions is of meshed pattern defined by the absence of a
polka dot pattern.
[0226] Still further in accordance with a preferred embodiment of
the invention the configuration-pattern of the bone contact surface
portions is of an hexagonal geometry.
[0227] Additionally the configuration-pattern of the bone contact
surface portions is of a spiral geometry defined by spiral
channels.
[0228] Further in accordance with a preferred embodiment of the
present invention the prosthesis (concave) includes a
configuration-pattern of the bone contact surface portions, which
includes a meshed pattern defined by the absence of a polka dot
pattern.
[0229] Still further in accordance with a preferred embodiment of
the present invention the bone contact surface and peripheral
channels surfaces is configured with a rough (not smooth)
texture.
[0230] Additionally in accordance with a preferred embodiment of
the present invention the bone contact surface and peripheral
channels surfaces is treated by atomic surface treatment.
[0231] Further in accordance with a preferred embodiment of the
present invention the bone contact surface and peripheral channels
surfaces is at least partially coated with a bioactive substance
stimulating bone-growth enhancing implant fixation to bone.
[0232] Preferably, the bioactive substance is Hydroxyapatite (HA:
Ca10(PO4)6(OH)2).
[0233] In accordance with another preferred embodiment of the
present invention a mesh of metal is configured in channels
generally in a floating position mostly clear of bottom and walls
of the channels. Alternatively, a mesh of composite material is
configured in channels generally in a floating positioning mostly
clear of bottom and walls of the channels. Preferably, the
composite material includes carbon. Additionally or alternatively,
the composite material includes KEVLAR.RTM.. Additionally or
alternatively, the composite material includes DYNEEMA.RTM..
[0234] Preferably, the mesh is embedded within bone contact
surfaces. Alternatively, the mesh is embedded within non-bone
contact surfaces.
[0235] There is further provided in accordance with another
preferred embodiment of the present invention an artificial
meniscus implant assembly formed by molding of polyurethane.
Preferably, the artificial meniscus implant assembly includes a
convex articulation surface and a concave articulation surface.
Additionally, the artificial meniscus implant assembly also
includes a bone snap-fit engagement element. Additionally or
alternatively, the artificial meniscus implant assembly also
includes at least one thoroughgoing aperture. Preferably, the
artificial meniscus implant assembly also includes at least one
tissue secure assembly.
[0236] In accordance with another preferred embodiment of the
present invention the tissue secure assembly includes an inner grip
element and a clip, and the clip has insert elements formed on each
end thereof.
[0237] There is also provided in accordance with yet another
preferred embodiment of the present invention an artificial patella
surface element formed by molding of polyurethane.
[0238] Preferably, the artificial patella surface element includes
a concave articulation surface. Additionally or alternatively, the
artificial patella surface element includes an outer peripheral
protrusion. Preferably, the outer peripheral protrusion is arranged
for snap-fit engagement with a corresponding recess provided by
machining of a patella. In accordance with another preferred
embodiment of the present invention, the artificial patella surface
element also includes at least one thoroughgoing aperture.
[0239] Preferably, the artificial patella surface element is
constructed to allow for deformation in response to an impact
force. Additionally, the deformation provides a shock-absorbing
effect to provide protection from the impact force. Additionally or
alternatively, the patella surface element returns to its original
orientation after the deformation.
[0240] There is still further provided in accordance with still
another preferred embodiment of the present invention an artificial
humeral surface element formed by molding of polyurethane.
[0241] Preferably, the artificial humeral surface element includes
a concave saddle shape surface for articulation with an ulna.
Alternatively, the artificial humeral surface element includes a
convex generally spherical surface for articulation with a
radius.
[0242] Preferably, the artificial humeral surface element includes
a peripheral protrusion element. Additionally, the peripheral
protrusion element is arranged for snap-fit engagement with
corresponding grooves formed by machining the humerus.
[0243] There is yet further provided in accordance with another
preferred embodiment of the present invention, an artificial ulnar
surface element formed by molding of polyurethane.
[0244] Preferably, the artificial ulnar surface element includes a
concave saddle shape surface for articulation with a humerus.
Additionally, the artificial ulnar surface element includes a
peripheral protrusion element. Preferably, the peripheral
protrusion element is arranged for snap-fit engagement with
corresponding grooves formed by machining the ulna.
[0245] There is also provided in accordance with yet another
preferred embodiment of the present invention an artificial radial
surface element formed by molding of polyurethane.
[0246] Preferably, the artificial radial surface element includes a
concave generally spherical surface for articulation with a
humerus. Additionally, the artificial radial surface element
includes a peripheral protrusion element. Preferably, the
peripheral protrusion element is arranged for snap-fit engagement
with corresponding grooves formed by machining the radius.
[0247] In accordance with another preferred embodiment of the
present invention, the implantable artificial socket for a joint is
foldable.
[0248] Additionally, the implantable artificial socket for a joint
also includes a deformation control element. Additionally, the
deformation element also includes a fluid absorption layer.
[0249] Further in accordance with another preferred embodiment of
the present invention the implantable artificial socket for a joint
also includes a radio opaque ring element.
[0250] In accordance with yet another preferred embodiment of the
present invention the implantable artificial socket for a joint
also includes a bioactive coating. Preferably, the bioactive
coating is formed by grit blasting. Alternatively, the bioactive
coating is formed by spraying. In accordance with another preferred
embodiment, the bioactive coating also includes an elastomer.
[0251] In accordance with still another preferred embodiment, the
implantable artificial socket for a joint also includes an
elastomer coating on an articulating surface.
[0252] In accordance with yet another preferred embodiment of the
present invention, the implantable artificial socket for a joint
also includes a thickened portion corresponding to the natural
acetabular notch.
[0253] Still further in accordance with another preferred
embodiment of the present invention, the implantable artificial
socket for a joint also includes an extended portion to prevent
dislocation of the natural femoral head following insertion
thereof. Alternatively, the implantable artificial socket for a
joint also includes an extended portion to prevent dislocation of
an artificial femoral head following insertion thereof.
[0254] In accordance with still another preferred embodiment of the
present invention, the implantable artificial socket for a joint
also includes recessed surface portions. Preferably, the recessed
surface portions are interconnected. Additionally or alternatively,
the recessed surface portions provide for the accumulation of
synovial fluid. Preferably, the synovial fluid is provided to
lubricate an articulation surface of the artificial socket.
[0255] In accordance with another preferred embodiment of the
present invention, the implantable artificial femoral head
resurfacing element is foldable.
[0256] Additionally, the implantable artificial femoral head
resurfacing element also includes a deformation control element.
Additionally, the deformation element also includes a fluid
absorption layer.
[0257] Further in accordance with another preferred embodiment of
the present invention the implantable artificial femoral head
resurfacing element also includes a radio opaque ring element.
[0258] In accordance with yet another preferred embodiment of the
present invention the implantable artificial femoral head
resurfacing element also includes a bioactive coating. Preferably,
the bioactive coating is formed by grit blasting. Alternatively,
the bioactive coating is formed by spraying. In accordance with
another preferred embodiment, the bioactive coating also includes
an elastomer.
[0259] In accordance with still another preferred embodiment, the
implantable artificial femoral head resurfacing element also
includes an elastomer coating on an articulating surface.
[0260] Further in accordance with another preferred embodiment of
the present invention the implantable artificial femoral head
resurfacing element also includes a femoral head interface element.
Preferably, the femoral head interface element is arranged for
snap-fit engagement with corresponding grooves formed by machining
the femur. Alternatively, the femoral head interface element is
arranged for press fit engagement with a corresponding seating
location formed by machining the femur. Additionally, the
implantable artificial femoral head resurfacing element is arranged
for snap-fit engagement with the femoral head interface element.
Alternatively, the femoral head resurfacing element is arranged for
press fit engagement with the femoral head interface element.
[0261] In accordance with still another preferred embodiment of the
present invention, the implantable artificial femoral head
resurfacing element also includes recessed surface portions.
Preferably, the recessed surface portions are interconnected.
Additionally or alternatively, the recessed surface portions
provide for the accumulation of synovial fluid. Preferably, the
synovial fluid is provided to lubricate an articulation surface of
the artificial socket.
BRIEF DESCRIPTION OF THE DRAWINGS
[0262] The present invention will be understood and appreciated
more fully from the following detailed description, taken in
conjunction with the drawings in which:
[0263] FIGS. 1A, 1B and 1C are respective pictorial, sectional and
partially cut away illustrations of an implantable artificial
socket for the acetabulum constructed and operative in accordance
with a preferred embodiment of the present invention;
[0264] FIGS. 2A, 2B and 2C are respective pictorial, sectional and
partially cut away illustrations of an implantable artificial
socket for the acetabulum constructed and operative in accordance
with another preferred embodiment of the present invention;
[0265] FIGS. 3A, 3B and 3C are respective pictorial, sectional and
partially cut away illustrations of an implantable artificial
socket for the acetabulum constructed and operative in accordance
with still another preferred embodiment of the present
invention;
[0266] FIGS. 4A, 4B and 4C are respective pictorial, sectional and
partially cut away illustrations of an implantable artificial
socket for the acetabulum constructed and operative in accordance
with yet another preferred embodiment of the present invention;
[0267] FIGS. 5A, 5B and 5C are respective pictorial, sectional and
partially cut away illustrations of an implantable artificial
socket for the acetabulum constructed and operative in accordance
with a further preferred embodiment of the present invention;
[0268] FIGS. 6A, 6B and 6C are respective pictorial, sectional and
partially cut away illustrations of an implantable artificial
femoral head resurfacing element constructed and operative in
accordance with a preferred embodiment of the present
invention;
[0269] FIGS. 7A, 7B and 7C are respective pictorial, sectional and
partially cut away illustrations of an implantable artificial
femoral head resurfacing element constructed and operative in
accordance with another preferred embodiment of the present
invention;
[0270] FIGS. 8A, 8B and 8C are respective pictorial, sectional and
partially cut away illustrations of an implantable artificial
femoral head resurfacing element constructed and operative in
accordance with still another preferred embodiment of the present
invention;
[0271] FIGS. 9A, 9B and 9C are respective pictorial, sectional and
partially cut away illustrations of an implantable artificial
femoral head resurfacing element constructed and operative in
accordance with yet another preferred embodiment of the present
invention;
[0272] FIGS. 10A, 10B and 10C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
femoral head resurfacing element constructed and operative in
accordance with a further preferred embodiment of the present
invention;
[0273] FIGS. 11A and 11B are respective exploded view and assembled
view illustrations of the implantable artificial socket of FIGS.
1A-1C in a total hip replacement environment;
[0274] FIGS. 12A and 12B are respective exploded view and assembled
view illustrations of the implantable artificial socket of FIGS.
1A-1C in a partial hip replacement environment;
[0275] FIGS. 13A and 13B are respective exploded view and assembled
view illustrations of the implantable artificial socket of FIGS.
1A-1C and the implantable artificial femoral head resurfacing
element of FIGS. 6A-6C in a total hip resurfacing environment;
[0276] FIGS. 14A and 14B are respective exploded view and assembled
view illustrations of the implantable artificial femoral head
resurfacing element of FIGS. 6A-6C in a hemi hip resurfacing
environment;
[0277] FIGS. 15A, 15B and 15C are respectively, an illustration of
an articulation surface, a sectional illustration and an
illustration of a bone engagement surface, of an implantable
artificial socket for the glenoid constructed and operative in
accordance with a preferred embodiment of the present
invention;
[0278] FIGS. 16A, 16B and 16C are respectively, an illustration of
an articulation surface, a sectional illustration and an
illustration of a bone engagement surface, of an implantable
artificial socket for the glenoid constructed and operative in
accordance with another preferred embodiment of the present
invention;
[0279] FIGS. 17A, 17B and 17C are respectively, an illustration of
an articulation surface, a sectional illustration and an
illustration of a bone engagement surface, of an implantable
artificial socket for the glenoid constructed and operative in
accordance with still another preferred embodiment of the present
invention;
[0280] FIGS. 18A, 18B and 18C are respectively, an illustration of
an articulation surface, a sectional illustration and an
illustration of a bone engagement surface, of an implantable
artificial socket for the glenoid constructed and operative in
accordance with yet another preferred embodiment of the present
invention;
[0281] FIGS. 19A, 19B and 19C are respectively, an illustration of
an articulation surface, a sectional illustration and an
illustration of a bone engagement surface, of an implantable
artificial socket for the glenoid constructed and operative in
accordance with a further preferred embodiment of the present
invention;
[0282] FIGS. 20A, 20B and 20C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
humeral head surface element constructed and operative in
accordance with a preferred embodiment of the present
invention;
[0283] FIGS. 21A, 21B and 21C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
humeral head surface element constructed and operative in
accordance with another preferred embodiment of the present
invention;
[0284] FIGS. 22A, 22B and 22C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
humeral head surface element constructed and operative in
accordance with still another preferred embodiment of the present
invention;
[0285] FIGS. 23A, 23B and 23C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
humeral head surface element constructed and operative in
accordance with yet another preferred embodiment of the present
invention;
[0286] FIGS. 24A, 24B and 24C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
humeral head surface element constructed and operative in
accordance with a further preferred embodiment of the present
invention;
[0287] FIGS. 25A and 25B are respective exploded view and assembled
view illustrations of the implantable artificial glenoid socket of
FIGS. 15A-15C in a total shoulder replacement environment;
[0288] FIGS. 26A and 26B are respective exploded view and assembled
view illustrations of the implantable artificial glenoid socket of
FIGS. 15A-15C in a partial shoulder replacement environment;
[0289] FIGS. 27A and 27B are respective exploded view and assembled
view illustrations of the implantable artificial humeral head
surface element of FIGS. 20A-20C in a hemi shoulder resurfacing
environment;
[0290] FIGS. 28A and 28B are respective exploded view and assembled
view illustrations of the implantable artificial glenoid socket of
FIGS. 15A-15C and the implantable artificial humeral head surface
element of FIGS. 20A-20C in a total shoulder resurfacing
environment;
[0291] FIGS. 29A and 29B are pictorial illustrations showing an
implantable artificial medial meniscus implant assembly constructed
and operative in accordance with a preferred embodiment of the
present invention;
[0292] FIGS. 30A and 30B are first and second pictorial
illustrations of an implantable artificial patella surface element
constructed and operative in a pre installation stage in accordance
with a preferred embodiment of the present invention;
[0293] FIGS. 31A, 31B and 31C are, respectively, a pictorial
illustration and sectional illustrations of the implantable
artificial patella surface element of FIGS. 30A and 30B installed
in patella;
[0294] FIGS. 32A and 32B are sectional illustrations of an
implantable artificial patella surface element of FIGS. 30A and 30B
in a patella replacement environment;
[0295] FIGS. 33A, 33B, 33C, 33D, 33E and 33F are respective first
and second pictorial, and first, second, third and fourth partially
cut away sectional illustrations of a pair of implantable
artificial humeral elbow surface elements constructed and operative
in accordance with a preferred embodiment of the present
invention;
[0296] FIGS. 34A, 34B, 34C, 34D, 34E and 34F are respective first
and second pictorial, and first, second, third and fourth sectional
illustrations of a pair of implantable artificial ulna and radius
elbow elements constructed and operative in accordance with a
preferred embodiment of the present invention;
[0297] FIGS. 35A and 35B are respective exploded view and assembled
view illustrations of the implantable artificial humeral elbow
elements of FIGS. 33A-33F in a partial elbow replacement
environment;
[0298] FIGS. 36A and 36B are respective exploded view and assembled
view illustrations of the implantable artificial ulna and radius
elbow elements of FIGS. 34A-34F in a partial elbow replacement
environment;
[0299] FIG. 37 is an assembled view illustration of the implantable
humeral elbow elements of FIGS. 33A-33F and the implantable
artificial ulna and radius elements of FIGS. 34A-34F in a total
elbow replacement environment;
[0300] FIGS. 38A, 38B, 38C and 38D are, respectively, a partially
cut away illustration and an exploded view illustration of a groove
reaming tool, and exploded and assembled view illustrations of a
portion of the groove reaming tool, constructed and operative in
accordance with a preferred embodiment of the present
invention;
[0301] FIGS. 39A and 39B are illustrations of another portion of
the groove reaming tool of FIGS. 38A, 38B, 38C and 38D in first and
second operative orientations;
[0302] FIGS. 40A, 40B, 40C, 40D, 40E, 40F and 40G are simplified
pictorial illustrations of various stages in groove reaming of an
acetabulum in accordance with a preferred embodiment of the present
invention;
[0303] FIGS. 41A, 41B, 41C and 41D are sectional illustrations
showing alternative reamed acetabulum configurations;
[0304] FIGS. 42A and 42B are simplified pictorial illustrations of
introduction and pre-snap fit placement of an implantable
artificial femoral head resurfacing element adjacent a reamed
femoral head in accordance with two alternative embodiments of the
present invention;
[0305] FIGS. 43A and 43B are simplified pictorial illustrations of
introduction and pre-snap fit placement of an implantable
artificial acetabular socket adjacent a reamed acetabulum in
accordance with two alternative embodiments of the present
invention;
[0306] FIGS. 44A, 44B, 44C and 44D are, respectively, a simplified
pictorial illustration and sectional illustrations of a snap-fit
installation of an implantable artificial acetabular socket in a
reamed acetabulum in accordance with a preferred embodiment of the
present invention;
[0307] FIGS. 45A and 45B are a simplified pictorial illustration
and a sectional illustration of a final stage in snap-fit
installation of an implantable artificial acetabular socket in a
reamed acetabulum in accordance with a preferred embodiment of the
present invention;
[0308] FIGS. 46A, 46B, 46C and 46D are respectively, a pictorial
illustration, two different sectional views and a partially cut
away pictorial illustration of an implantable artificial acetabular
socket constructed and operative in accordance with a further
preferred embodiment of the present invention;
[0309] FIGS. 47A, 47B and 47C are respectively, a pictorial and two
partially cut away illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with
another preferred embodiment of the present invention;
[0310] FIGS. 48A, 48B, 48C and 48D are partially cut away pictorial
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with still another
preferred embodiment of the present invention;
[0311] FIGS. 49A and 49B are respective pictorial and partially cut
away illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with yet another preferred
embodiment of the present invention;
[0312] FIGS. 50A and 50B are respective pictorial and partially cut
away illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a further preferred
embodiment of the present invention;
[0313] FIGS. 51A, 51B and 51C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
femoral head resurfacing element constructed and operative in
accordance with a further preferred embodiment of the present
invention;
[0314] FIGS. 52A, 52B and 52C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
femoral head resurfacing element constructed and operative in
accordance with another preferred embodiment of the present
invention;
[0315] FIGS. 53A, 53B and 53C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
femoral head resurfacing element constructed and operative in
accordance with still another preferred embodiment of the present
invention;
[0316] FIGS. 54A, 54B and 54C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
femoral head resurfacing element constructed and operative in
accordance with yet another preferred embodiment of the present
invention;
[0317] FIGS. 55A, 55B and 55C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
femoral head resurfacing element constructed and operative in
accordance with a further preferred embodiment of the present
invention;
[0318] FIGS. 56A, 56B and 56C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with a
further preferred embodiment of the present invention;
[0319] FIGS. 57A, 57B and 57C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with
another preferred embodiment of the present invention;
[0320] FIGS. 58A and 58B are respective partially cut away
pictorial and sectional illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with
still another preferred embodiment of the present invention;
[0321] FIGS. 59A and 59B are respective partially cut away
pictorial and sectional illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with yet
another preferred embodiment of the present invention;
[0322] FIGS. 60A, 60B and 60C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with a
further preferred embodiment of the present invention;
[0323] FIGS. 61A, 61B and 61C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
femoral head resurfacing element constructed and operative in
accordance with a further preferred embodiment of the present
invention;
[0324] FIGS. 62A, 62B and 62C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
femoral head resurfacing element constructed and operative in
accordance with another preferred embodiment of the present
invention;
[0325] FIGS. 63A and 63B are respective pictorial, sectional and
partially cut away illustrations of an implantable artificial
femoral or humeral head resurfacing element constructed and
operative in accordance with still another preferred embodiment of
the present invention;
[0326] FIGS. 64A and 64B are respective pictorial and sectional
illustrations of an implantable artificial femoral or humeral head
resurfacing element constructed and operative in accordance with
yet another preferred embodiment of the present invention;
[0327] FIGS. 65A, 65B and 65C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
femoral or humeral head resurfacing element constructed and
operative in accordance with a further preferred embodiment of the
present invention;
[0328] FIGS. 66A, 66B, and 66C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with a
further preferred embodiment of the present invention;
[0329] FIGS. 67A, 67B, and 67C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with
another preferred embodiment of the present invention;
[0330] FIGS. 68A, 68B, and 68C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with yet
another preferred embodiment of the present invention;
[0331] FIGS. 69A, 69B, 69C and 69D are sectional illustrations of a
hip joint employing the implantable artificial acetabular sockets
of FIGS. 66A-68C implanted in a reamed acetabulum;
[0332] FIGS. 70A, 70B, and 70C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with a
further preferred embodiment of the present invention;
[0333] FIGS. 71A, 71B, and 71C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with
another preferred embodiment of the present invention;
[0334] FIGS 72A, 72B, and 72C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with
still another preferred embodiment of the present invention;
[0335] FIGS. 73A and 73B are respective pictorial and sectional
illustrations of an implantable artificial femoral or humeral head
resurfacing element constructed and operative in accordance with a
further preferred embodiment of the present invention;
[0336] FIGS. 74A and 74B are respective pictorial and sectional
illustrations of an implantable artificial femoral or humeral head
resurfacing element constructed and operative in accordance with
another preferred embodiment of the present invention;
[0337] FIGS. 75A and 75B are respective pictorial and sectional
illustrations of an implantable artificial femoral or humeral head
resurfacing element constructed and operative in accordance with
still another preferred embodiment of the present invention;
[0338] FIGS. 76A and 76B are respective pictorial and sectional
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a further preferred
embodiment of the present invention;
[0339] FIGS. 77A and 77B are respective pictorial and sectional
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with another preferred
embodiment of the present invention;
[0340] FIGS. 78A and 78B are respective pictorial and sectional
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with still another
preferred embodiment of the present invention;
[0341] FIGS. 79A and 79B are respective pictorial and sectional
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a further preferred
embodiment of the present invention;
[0342] FIGS. 80A, 80B, and 80C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with
another preferred embodiment of the present invention;
[0343] FIGS. 81A, 81B, and 81C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with
still another preferred embodiment of the present invention;
[0344] FIGS. 82A, 82B, and 82C are respective pictorial, sectional
and partially cut away illustrations of an implantable artificial
acetabular socket constructed and operative in accordance with a
further preferred embodiment of the present invention;
[0345] FIG. 83 is a pictorial illustration of an implantable
artificial acetabular socket constructed and operative in
accordance with another preferred embodiment of the present
invention;
[0346] FIG. 84 is a pictorial illustration of an implantable
artificial acetabular socket constructed and operative in
accordance with still another preferred embodiment of the present
invention;
[0347] FIGS. 85A and 85B are sectional illustrations of the
installation of an artificial femoral head on a reamed femoral
head, in accordance with a preferred embodiment of the present
invention;
[0348] FIGS. 86A and 86B are sectional illustrations of the
installation of an artificial femoral head on a reamed femoral
head, in accordance with another preferred embodiment of the
present invention;
[0349] FIGS. 87A, 87B, 87C and 87D are sectional illustrations of
various stages of installation of a multi-part artificial femoral
head on a reamed femoral head in accordance with still another
preferred embodiment of the present invention;
[0350] FIGS. 88A, 88B, 88C and 88D are sectional illustrations of
various stages of installation of a multi-part artificial femoral
head on a reamed femoral head in accordance with yet another
preferred embodiment of the present invention;
[0351] FIGS. 89A and 89B are sectional illustrations of various
stages of installation of a multi-part artificial femoral head on a
reamed femoral head, in accordance with a further preferred
embodiment of the present invention;
[0352] FIG. 90A is a sectional illustration of the installation of
a multi-part artificial femoral head on a conventional stem in
accordance with still another preferred embodiment of the present
invention;
[0353] FIG. 90B is a sectional illustration of the installation of
a multi-part artificial humeral head on a conventional stem in
accordance with yet another preferred embodiment of the present
invention;
[0354] FIGS. 91A, 91B and 91C are sectional illustrations showing
bone growth adjacent to an implanted acetabular socket in
accordance with another preferred embodiment of the present
invention;
[0355] FIG. 92 is a simplified sectional illustration of a bone
engagement surface, textured in accordance with another preferred
embodiment of the present invention;
[0356] FIGS. 93A and 93B are simplified pictorial illustrations of
a method of modifying the texture of a bone engagement surface of
an artificial implantation device, in accordance with another
preferred embodiment of the present invention;
[0357] FIG. 94 is a simplified pictorial illustration of another
method of modifying the texture of the bone engagement surface of
an artificial implantation device, in accordance with yet another
preferred embodiment of the present invention; and
[0358] FIG. 95 is a simplified pictorial illustration of a spraying
apparatus which may be used in the embodiment of FIG. 94.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0359] Reference is now made to FIGS. 1A, 1B and 1C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial socket constructed and
operative in accordance with a preferred embodiment of the present
invention and which is particularly suitable for use in a hip
joint.
[0360] As seen in FIGS. 1A, 1B and 1C, an implantable artificial
acetabular socket, designated by reference numeral 1100, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0361] Preferably, implantable artificial acetabular socket 1100 is
of generally uniform thickness, is symmetric about an axis 1101 and
defines an hemispherical concave inner articulation surface 1102,
having a beveled edge 1103, and a generally hemispherical outer
bone engagement surface 1104, which preferably has formed thereon,
at any suitable location between its apex and its rim, a generally
annular outwardly extending protrusion 1106, preferably defining a
generally annular undercut 1108. Alternatively, the protrusion 1106
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 1106 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinbelow.
[0362] Preferably, the protrusion 1106 has a cross-sectional
configuration, as can be readily seen in FIG. 1B, which is
characterized in that an underlying surface portion 1110 of
protrusion 1106, at the undercut 1108, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
1112 of protrusion 1106.
[0363] Reference is now made to FIGS. 2A, 2B and 2C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with another preferred
embodiment of the present invention.
[0364] As seen in FIGS. 2A, 2B and 2C, an implantable artificial
acetabular socket, designated by reference numeral 1200, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0365] Preferably, implantable artificial acetabular socket 1200 is
of generally uniform thickness, is symmetric about an axis 1201 and
defines an hemispherical inner articulation surface 1202, having a
beveled edge 1203, and a generally hemispherical outer bone
engagement surface 1204 which preferably has formed thereon, at any
suitable location between its apex and its rim, a generally annular
outwardly extending array 1206 of discrete protrusions 1207,
preferably defining a generally annular array 1208 of undercuts
1209. Alternatively, the array 1206 may be any other suitable
non-annular, open or closed, generally peripheral, array of
protrusions. The array 1206 of protrusions 1207 is preferably
arranged for snap-fit engagement with corresponding grooves formed
inter alia by reaming of a bone, examples of which are described
hereinbelow
[0366] Preferably, the protrusions 1207 have a cross-sectional
configuration, as can be readily seen in FIG. 2B, which is
characterized in that an underlying surface portion 1210 of each
protrusion 1207, at the undercut 1209, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
1212 of the protrusion 1207.
[0367] Reference is now made to FIGS. 3A, 3B and 3C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with still another
preferred embodiment of the present invention.
[0368] As seen in FIGS. 3A, 3B and 3C, an implantable artificial
acetabular socket, designated by reference numeral 1300, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0369] Preferably, implantable artificial acetabular socket 1300 is
of generally uniform thickness, is symmetric about an axis 1301 and
defines an hemispherical inner articulation surface 1302, having a
beveled edge 1303, and a generally hemispherical outer bone
engagement surface 1304 which preferably has formed thereon, at any
suitable location between its apex and its rim, a generally annular
outwardly extending array 1306 of discrete protrusions 1307,
preferably defining a generally annular array 1308 of undercuts
1309. Alternatively, the array 1306 may be any other suitable
non-annular, open or closed, generally peripheral, array of
protrusions. The array 1306 of protrusions 1307 is preferably
arranged for snap-fit engagement with corresponding recesses formed
inter alia by suitable machining of a bone.
[0370] Preferably, the protrusions 1307 have a generally
button-like configuration which is symmetric about an axis 1310 and
include a body portion 1311 and an enlarged head portion 1312, as
can be readily seen in FIG. 3B. Protrusions 1307 are generally
characterized in that an underlying surface portion 1313 of each
protrusion 1307 defines peripheral undercut 1309 with respect to
axis 1310.
[0371] Reference is now made to FIGS. 4A, 4B and 4C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with yet another preferred
embodiment of the present invention.
[0372] As seen in FIGS. 4A, 4B and 4C, an implantable artificial
acetabular socket, designated by reference numeral 1400, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0373] Preferably, implantable artificial acetabular socket 1400 is
of generally uniform thickness, is symmetric about an axis 1401 and
defines an hemispherical inner articulation surface 1402, having a
beveled edge 1403, and a generally hemispherical outer bone
engagement surface 1404 which preferably has formed thereon, at any
suitable location between its apex and its rim, a generally annular
inwardly extending recess 1406, preferably defining a generally
annular undercut 1408. Alternatively, the recess 1406 may be any
other suitable non-annular, open or closed, generally peripheral,
recess. The recess 1406 is preferably arranged for snap-fit
engagement with a corresponding protrusion formed by reaming of a
bone, examples of which are described hereinbelow.
[0374] Preferably, the recess 1406 has a cross-sectional
configuration, as can be readily seen in FIG. 4B, which is
characterized in that an overlying surface portion 1410 of recess
1406, at the undercut 1408, defines a slope which is sharper than a
corresponding slope of an underlying surface portion 1412 of recess
1406.
[0375] Reference is now made to FIGS. 5A, 5B and 5C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with still another
preferred embodiment of the present invention.
[0376] As seen in FIGS. 5A, 5B and 5C, an implantable artificial
acetabular socket, designated by reference numeral 1500, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0377] Preferably, implantable artificial acetabular socket 1500 is
of generally uniform thickness, is symmetric about an axis 1501 and
defines an hemispherical inner articulation surface 1502, having a
beveled edge 1503, and a generally hemispherical outer bone
engagement surface 1504 which preferably has formed thereon, at any
suitable location between its apex and its rim, a generally annular
inwardly extending array 1506 of discrete recesses 1507, preferably
defining a generally annular array 1508 of undercuts 1509.
Alternatively, the array 1506 may be any other suitable
non-annular, open or closed, generally peripheral, array of
recesses. The array 1506 of recesses 1507 is preferably arranged
for snap-fit engagement with corresponding protrusions formed inter
alia by suitable machining of a bone.
[0378] Preferably, the recesses 1507 have a generally button-like
configuration which is symmetric about an axis 1510 and include a
body portion 1511 and an enlarged head portion 1512, as can be
readily seen in FIG. 5B. Recesses 1507 are generally characterized
in that an overlying surface portion 1513 of each recess 1507
defines a peripheral undercut with respect to axis 1510.
[0379] Reference is now made to FIGS. 6A, 6B and 6C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial femoral head resurfacing
element constructed and operative in accordance with a preferred
embodiment of the present invention. The implantable artificial
femoral head resurfacing element is intended for mounting onto a
natural femoral head in accordance with a preferred embodiment of
the present invention.
[0380] As seen in FIGS. 6A, 6B and 6C, an implantable artificial
femoral head resurfacing element, designated by reference numeral
1600, is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0381] Preferably, implantable artificial femoral head resurfacing
element 1600 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about an axis 1601 and
defines an hemispherical outer articulation surface 1602 and a
generally hemispherical inner bone engagement surface 1604, having
a beveled edge 1605, which preferably has formed thereon, at any
suitable location between its apex and its rim, a generally annular
inwardly extending protrusion 1606, preferably defining a generally
annular undercut 1608. Alternatively, the protrusion 1606 may be
any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 1606 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a femoral head.
[0382] Preferably, the protrusion 1606 has a cross-sectional
configuration, as can be readily seen in FIG. 6B, which is
characterized in that an underlying surface portion 1610 of
protrusion 1606, at the undercut 1608, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
1612 of protrusion 1606.
[0383] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
femoral head resurfacing element 1600 at the apex thereof, any
suitable portion thereof may be of non-uniform thickness.
[0384] Reference is now made to FIGS. 7A, 7B and 7C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial femoral head resurfacing
element constructed and operative in accordance with another
preferred embodiment of the present invention.
[0385] As seen in FIGS. 7A, 7B and 7C, an implantable artificial
femoral head resurfacing element, designated by reference numeral
1700, is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0386] Preferably, implantable artificial femoral head resurfacing
element 1700 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about an axis 1701 and
defines an hemispherical outer articulation surface 1702 and a
generally hemispherical inner bone engagement surface 1704, having
a beveled edge 1705, which preferably has formed thereon, at any
suitable location between its apex and its rim, a generally annular
inwardly extending array 1706 of discrete protrusions 1707,
preferably defining a generally annular array 1708 of undercuts
1709. Alternatively, the array 1706 may be any other suitable
non-annular, open or closed, generally peripheral, array of
protrusions. The array 1706 of protrusions 1707 is preferably
arranged for snap-fit engagement with corresponding grooves formed
inter alia by reaming of a femoral head.
[0387] Preferably, the protrusions 1707 have a cross-sectional
configuration, as can be readily seen in FIG. 7B, which is
characterized in that an underlying surface portion 1710 of each
protrusion 1707, at the undercut 1709, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
1712 of the protrusion 1707.
[0388] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
femoral head resurfacing element 1700 at the apex thereof, any
suitable portion thereof may be of non-uniform thickness.
[0389] Reference is now made to FIGS. 8A, 8B and 8C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial femoral head resurfacing
element constructed and operative in accordance with still another
preferred embodiment of the present invention.
[0390] As seen in FIGS. 8A, 8B and 8C, an implantable artificial
femoral head resurfacing element, designated by reference numeral
1800, is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0391] Preferably, implantable artificial femoral head resurfacing
element 1800 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about an axis 1801 and
defines an hemispherical outer articulation surface 1802 and a
generally hemispherical inner bone engagement surface 1804, having
a beveled edge 1805, which preferably has formed thereon, at any
suitable location between its apex and its rim, a generally annular
inwardly extending array 1806 of discrete protrusions 1807,
preferably defining a generally annular array 1808 of undercuts
1809. Alternatively, the array 1806 may be any other suitable
non-annular, open or closed, generally peripheral, array of
protrusions. The array 1806 of protrusions 1807 is preferably
arranged for snap-fit engagement with corresponding recesses formed
inter alia by suitable machining of a femoral head.
[0392] Preferably, the protrusions 1807 have a generally
button-like configuration which is symmetric about an axis 1810 and
include a body portion 1811 and an enlarged head portion 1812, as
can be readily seen in FIG. 8B. Protrusions 1807 are generally
characterized in that an underlying surface portion 1813 of each
protrusion 1807 defines the peripheral undercut 1809 with respect
to axis 1810.
[0393] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
femoral head resurfacing element 1800 at the apex thereof, any
suitable portion thereof may be of non-uniform thickness.
[0394] Reference is now made to FIGS. 9A, 9B and 9C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial femoral head resurfacing
element constructed and operative in accordance with yet another
preferred embodiment of the present invention.
[0395] As seen in FIGS. 9A, 9B and 9C, an implantable artificial
femoral head resurfacing element, designated by reference numeral
1900, is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0396] Preferably, implantable artificial femoral head resurfacing
element 1900 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about an axis 1901 and
defines an hemispherical outer articulation surface 1902 and a
generally hemispherical inner bone engagement surface 1904, having
a beveled edge 1905, which preferably has formed thereon, at any
suitable location between its apex and its rim, a generally annular
outwardly extending recess 1906, preferably defining a generally
annular undercut 1908. Alternatively, the recess 1906 may be any
other suitable non-annular, open or closed, generally peripheral,
protrusion. The recess 1906 is preferably arranged for snap-fit
engagement with a corresponding protrusion formed by reaming of a
femoral head.
[0397] Preferably, the recess 1906 has a cross-sectional
configuration, as can be readily seen in FIG. 9B, which is
characterized in that an overlying surface portion 1910 of recess
1906, at the undercut 1908, defines a slope which is sharper than a
corresponding slope of an underlying surface portion 1912 of recess
1906.
[0398] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
femoral head resurfacing element 1900 at the apex thereof, any
suitable portion thereof may be of non-uniform thickness.
[0399] Reference is now made to FIGS. 10A, 10B and 10C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial femoral head resurfacing
element constructed and operative in accordance with still another
preferred embodiment of the present invention.
[0400] As seen in FIGS. 10A, 10B and 10C, an implantable artificial
femoral head resurfacing element, designated by reference numeral
2000, is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0401] Preferably, implantable artificial femoral head resurfacing
element 2000 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about an axis 2001 and
defines an hemispherical outer articulation surface 2002 and a
generally hemispherical inner bone engagement surface 2004, having
a beveled edge 2005, which preferably has formed thereon, at any
suitable location between its apex and its rim, a generally annular
outwardly extending array 2006 of discrete recesses 2007,
preferably defining a generally annular array 2008 of undercuts
2009. Alternatively, the array 2006 may be any other suitable
non-annular, open or closed, generally peripheral, array of
recesses. The array 2006 of recesses 2007 is preferably arranged
for snap-fit engagement with corresponding protrusions formed inter
alia by suitable machining of a femoral head.
[0402] Preferably, the recesses 2007 have a generally button-like
configuration which is symmetric about an axis 2010 and include a
body portion 2011 and an enlarged head portion 2012, as can be
readily seen in FIG. 10B. Recesses 2007 are generally characterized
in that an overlying surface portion 2013 of each recess 2007
defines peripheral undercut 2009 with respect to axis 2010.
[0403] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
femoral head resurfacing element 2000 at the apex thereof, any
suitable portion thereof may be of non-uniform thickness.
[0404] Reference is now made to FIGS. 11A and 11B, which are
respective exploded view and assembled view illustrations of the
implantable artificial acetabular socket of FIGS. 1A-1C in a total
hip replacement environment. As seen in FIGS. 11A and 11B,
implantable artificial acetabular socket 1100 (FIGS. 1A-1C) is
snap-fitted into a suitably machined natural acetabulum of a
patient. A conventional artificial femoral head 2100 is mounted
onto a conventional femoral stem 2102 and is arranged for
articulation with articulation surface 1102 of socket 1100.
[0405] Reference is now made to FIGS. 12A and 12B, which are
respective exploded view and assembled view illustrations of the
implantable artificial acetabular socket of FIGS. 1A-1C in a
partial hip replacement environment. As seen in FIGS. 12A and 12B,
implantable artificial acetabular socket 1100 (FIGS. 1A-1C) is
snap-fitted into a suitably machined natural acetabulum of a
patient. A natural femoral head 2200 is arranged for articulation
with articulation surface 1102 of socket 1100.
[0406] It is a particular feature of the embodiment of FIGS. 12A
and 12B that the size and configuration of articulation surface
1102 of artificial acetabular socket 1100 is made to be identical
to that of the natural acetabular socket of the patient, in order
that the natural femoral head 2200 may articulate therewith with
desired dimensional clearances and without requiring machining of
the femoral head. The ability of the articulation surface 1102 of
socket 1100 to be identical to that of the natural femoral head
2200 is provided by the flexibility and resiliency of artificial
acetabular socket 1100, which enables small adjustments in the size
and configuration of the articulation surface 1102 to be realized
by suitably exact machining of the natural acetabular socket.
[0407] Reference is now made to FIGS. 13A and 13B, which are
respective exploded view and assembled view illustrations of the
implantable artificial acetabular socket of FIGS. 1A-1C and the
implantable artificial femoral head resurfacing element of FIGS.
6A-6C in a total hip resurfacing environment. As seen in FIGS. 13A
and 13B, implantable artificial acetabular socket 1100 (FIGS.
1A-1C) is snap-fitted into a suitably machined natural acetabulum
of a patient. A suitably machined natural femoral head 2300 having
the implantable artificial femoral head resurfacing element 1600 of
FIGS. 6A-6C snap-fit mounted thereon is arranged for articulation
of articulation surface 1602 thereof with articulation surface 1102
of socket 1100.
[0408] Reference is now made to FIGS. 14A and 14B, which are
respective exploded view and assembled view illustrations of the
implantable artificial femoral head resurfacing element of FIGS.
6A-6C in a hemi hip resurfacing environment. As seen in FIGS. 14A
and 14B, a suitably machined natural femoral head 2400 having the
implantable artificial femoral head resurfacing element 1600 of
FIGS. 6A-6C snap-fit mounted thereon is arranged for articulation
of articulation surface 1602 thereof with a natural articulation
surface of a natural acetabulum.
[0409] It is a particular feature of the embodiment of FIGS. 14A
and 14B that the size and configuration of articulation surface
1602 of artificial femoral head resurfacing element 1600 is made to
be identical to that of the natural acetabular socket of the
patient, in order that the natural femoral head 2400 onto which
artificial femoral head resurfacing element 1600 is mounted may
articulate therewith with desired dimensional clearances and
without requiring machining of the natural acetabulum. The ability
of the articulation surface 1602 of femoral head resurfacing
element 1600 to be identical to that of the natural acetabulum is
provided by the flexibility and resiliency of artificial femoral
head resurfacing element 1600, which enables small adjustments in
the size and configuration of the articulation surface 1602 to be
realized by suitably exact machining of the femoral head.
[0410] Reference is now made to FIGS. 15A, 15B and 15C, which are
respectively, an illustration of an articulation surface, a
sectional illustration and an illustration of a bone engagement
surface, of an implantable artificial glenoid socket constructed
and operative in accordance with a preferred embodiment of the
present invention and which is particularly useful for a shoulder
joint.
[0411] As seen in FIGS. 15A, 15B and 15C, an implantable artificial
glenoid socket, designated by reference numeral 2500, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0412] Preferably, implantable artificial glenoid socket 2500 is of
generally uniform thickness and defines an articulation surface
2502, which defines a portion of a concave spherical surface, and a
bone engagement surface 2504. Bone engagement surface 2504
preferably has formed thereon multiple protrusions. In the
illustrated embodiment, there are provided inner and outer
protrusions, respectively designated by reference numerals 2506 and
2508, defining respective undercuts 2510 and 2512. Alternatively,
protrusions 2506 and 2508 may be any other suitable open or closed
protrusions. Protrusions 2506 and 2508 are preferably arranged for
snap-fit engagement with corresponding grooves formed by machining
of the glenoid.
[0413] Reference is now made to FIGS. 16A, 16B and 16C, which are
respectively, an illustration of an articulation surface, a
sectional illustration and an illustration of a bone engagement
surface, of an implantable artificial glenoid socket constructed
and operative in accordance with another preferred embodiment of
the present invention.
[0414] As seen in FIGS. 16A, 16B and 16C, an implantable artificial
glenoid socket, designated by reference numeral 2600, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0415] Preferably, implantable artificial glenoid socket 2600 is of
generally uniform thickness and defines an articulation surface
2602, which defines a portion of a concave spherical surface, and a
bone engagement surface 2604. Bone engagement surface 2604
preferably has formed thereon multiple protrusions. In the
illustrated embodiment, there are provided inner and outer arrays
of protrusions, the arrays being respectively designated by
reference numerals 2606 and 2608, defining respective undercuts
2610 and 2612. Alternatively, protrusions of arrays 2606 and 2608
may be any other suitable open or closed protrusions. Protrusions
2606 and 2608 are preferably arranged for snap-fit engagement with
corresponding grooves formed by machining of the glenoid.
[0416] Reference is now made to FIGS. 17A, 17B and 17C, which are
respectively, an illustration of an articulation surface, a
sectional illustration and an illustration of a bone engagement
surface, of an implantable artificial glenoid socket constructed
and operative in accordance with yet another preferred embodiment
of the present invention.
[0417] As seen in FIGS. 17A, 17B and 17C, an implantable artificial
glenoid socket, designated by reference numeral 2700, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0418] Preferably, implantable artificial glenoid socket 2700 is of
generally uniform thickness and defines an articulation surface
2702, which defines a portion of a concave spherical surface, and a
bone engagement surface 2704. Bone engagement surface 2704
preferably has formed thereon multiple protrusions. In the
illustrated embodiment, there are provided an inner array of
protrusions 2706 and an outer peripheral protrusion 2708, defining
respective undercuts 2710 and 2712. Alternatively, protrusions of
array 2706 and protrusion 2708 may be any other suitable open or
closed protrusions. Protrusions of array 2706 and protrusion 2708
are preferably arranged for snap-fit engagement with corresponding
grooves formed by machining of the glenoid.
[0419] Preferably, at least some of the protrusions of array 2706,
here designated as protrusions 2713 have a generally button-like
configuration which is symmetric about an axis 2714 and include a
body portion 2715 and an enlarged head portion 2716, as can be
readily seen in FIG. 17B. Protrusions 2713 are generally
characterized in that an underlying surface portion 2717 of each
protrusion 2713 defines peripheral undercut 2710 with respect to
axis 2714.
[0420] Reference is now made to FIGS. 18A, 18B and 18C, which are
respectively, an illustration of an articulation surface, a
sectional illustration and an illustration of a bone engagement
surface, of an implantable artificial glenoid socket constructed
and operative in accordance with still another preferred embodiment
of the present invention.
[0421] As seen in FIGS. 18A, 18B and 18C, an implantable artificial
glenoid socket, designated by reference numeral 2800, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0422] Preferably, implantable artificial glenoid socket 2800 is of
generally uniform thickness and defines an articulation surface
2802, which defines a portion of a concave spherical surface, and a
bone engagement surface 2804. Bone engagement surface 2804
preferably has formed thereon an inner recess and an outer
protrusion, respectively designated by reference numerals 2806 and
2808, defining respective undercuts 2810 and 2812. Alternatively,
recess 2806 and protrusion 2808 may be any other suitable, open or
closed, recesses or protrusions, respectively. Recess 2806 and
protrusion 2808 are preferably arranged for snap-fit engagement
with corresponding protrusions and grooves respectively formed by
machining of the glenoid.
[0423] Reference is now made to FIGS. 19A, 19B and 19C, which are
respectively, an illustration of an articulation surface, a
sectional illustration and an illustration of a bone engagement
surface, of an implantable artificial glenoid socket constructed
and operative in accordance with yet another preferred embodiment
of the present invention.
[0424] As seen in FIGS. 19A, 19B and 19C, an implantable artificial
glenoid socket, designated by reference numeral 2900, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0425] Preferably, implantable artificial glenoid socket 2900 is of
generally uniform thickness and defines an articulation surface
2902, which defines a portion of a concave spherical surface, and a
bone engagement surface 2904. Bone engagement surface 2904
preferably has formed thereon multiple recesses and/or protrusions.
In the illustrated embodiment, there are provided an inner array of
recesses 2906 and an outer peripheral protrusion 2908, defining
respective undercuts 2910 and 2912. Alternatively, recesses of
array 2906 and protrusion 2908 may be any other suitable, open or
closed, recesses and protrusion, respectively. Recesses of array
2906 and protrusion 2908 are preferably arranged for snap-fit
engagement with corresponding protrusions and grooves respectively,
formed by machining of the glenoid.
[0426] Preferably, at least some of the recesses of array 2906,
here designated as recesses 2913, have a generally button-like
configuration which is symmetric about an axis 2914 and include a
body portion 2915 and an enlarged head portion 2916, as can be
readily seen in FIG. 19B. Recesses 2913 are generally characterized
in that an underlying surface portion 2917 of each protrusion 2913
defines peripheral undercut 2910 with respect to axis 2914.
[0427] Reference is now made to FIGS. 20A, 20B and 20C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial humeral head surface
element constructed and operative in accordance with a preferred
embodiment of the present invention. The implantable artificial
humeral head surface element is intended for mounting onto a
natural humeral head in accordance with a preferred embodiment of
the present invention.
[0428] As seen in FIGS. 20A, 20B and 20C, an implantable artificial
humeral head surface element, designated by reference numeral 3000,
is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0429] Preferably, implantable artificial humeral head surface
element 3000 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about an axis 3001 and
defines an articulation surface 3002, which defines a portion of a
convex spherical surface, and a bone engagement surface 3004,
having a beveled edge 3005, which preferably has formed thereon, at
any suitable location between its apex and its rim, a generally
annular inwardly extending protrusion 3006, preferably defining a
generally annular undercut 3008. Alternatively, the protrusion 3006
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 3006 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a humeral head.
[0430] Preferably, the protrusion 3006 has a cross-sectional
configuration, as can be readily seen in FIG. 20B, which is
characterized in that an underlying surface portion 3010 of
protrusion 3006, at the undercut 3008, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
3012 of protrusion 3006.
[0431] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
humeral head surface element 3000 at the apex thereof, any suitable
portion thereof may be of non-uniform thickness.
[0432] Reference is now made to FIGS. 21A, 21B and 21C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial humeral head surface
element constructed and operative in accordance with another
preferred embodiment of the present invention.
[0433] As seen in FIGS. 21A, 21B and 21C, an implantable artificial
humeral head surface element, designated by reference numeral 3100,
is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0434] Preferably, implantable artificial humeral head surface
element 3100 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about an axis 3101 and
defines an articulation surface 3102, which defines a portion of a
convex spherical surface, and a bone engagement surface 3104,
having a beveled edge 3105, which preferably has formed thereon, at
any suitable location between its apex and its rim, a generally
annular inwardly extending array 3106 of discrete protrusions 3107,
preferably defining a generally annular array 3108 of undercuts
3109. Alternatively, the array 3106 may be any other suitable
non-annular, open or closed, generally peripheral, array of
protrusions. The array 3106 of protrusions 3107 is preferably
arranged for snap-fit engagement with corresponding grooves formed
inter alia by reaming of a humeral head.
[0435] Preferably, the protrusions 3107 have a cross-sectional
configuration, as can be readily seen in FIG. 21B, which is
characterized in that an underlying surface portion 3110 of each
protrusion 3107, at the undercut 3109, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
3112 of the protrusion 3107
[0436] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
humeral head surface element 3100 at the apex thereof, any suitable
portion thereof may be of non-uniform thickness.
[0437] Reference is now made to FIGS. 22A, 22B and 22C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial humeral head surface
element constructed and operative in accordance with still another
preferred embodiment of the present invention.
[0438] As seen in FIGS. 22A, 22B and 22C, an implantable artificial
humeral head surface element, designated by reference numeral 3200,
is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0439] Preferably, implantable artificial humeral head surface
element 3200 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about an axis 3201 and
defines an articulation surface 3202, which defines a portion of a
convex spherical surface, and a bone engagement surface 3204,
having a beveled edge 3205, which preferably has formed thereon, at
any suitable location between its apex and its rim, a generally
annular inwardly extending array 3206 of discrete protrusions 3207,
preferably defining a generally annular array 3208 of undercuts
3209. Alternatively, the array 3206 may be any other suitable
non-annular, open or closed, generally peripheral, array of
protrusions. The array 3206 of protrusions 3207 is preferably
arranged for snap-fit engagement with corresponding recesses formed
inter alia by suitable machining of a humeral head.
[0440] Preferably, the protrusions 3207 have a generally
button-like configuration which is symmetric about an axis 3210 and
include a body portion 3211 and an enlarged head portion 3212, as
can be readily seen in FIG. 22B. Protrusions 3207 are generally
characterized in that an underlying surface portion 3213 of each
protrusion 3207 defines peripheral undercut 3209 with respect to
axis 3210.
[0441] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
humeral head surface element 3200 at the apex thereof, any suitable
portion thereof may be of non-uniform thickness.
[0442] Reference is now made to FIGS. 23A, 23B and 23C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial humeral head surface
element constructed and operative in accordance with yet another
preferred embodiment of the present invention.
[0443] As seen in FIGS. 23A, 23B and 23C, an implantable artificial
humeral head surface element, designated by reference numeral 3300,
is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0444] Preferably, implantable artificial humeral head surface
element 3300 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about an axis 3301 and
defines an articulation surface 3302, which defines a portion of a
convex spherical surface, and a bone engagement surface 3304,
having a beveled edge 3305, which preferably has formed thereon, at
any suitable location between its apex and its rim, a generally
annular outwardly extending recess 3306, preferably defining a
generally annular undercut 3308. Alternatively, the recess 3306 may
be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The recess 3306 is preferably arranged for
snap-fit engagement with a corresponding protrusion formed by
reaming of a humeral head.
[0445] Preferably, the recess 3306 has a cross-sectional
configuration, as can be readily seen in FIG. 23B, which is
characterized in that an overlying surface portion 3310 of recess
3306, at the undercut 3308, defines a slope which is sharper than a
corresponding slope of an underlying surface portion 3312 of recess
3306.
[0446] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
humeral head surface element 3300 at the apex thereof, any suitable
portion thereof may be of non-uniform thickness.
[0447] Reference is now made to FIGS. 24A, 24B and 24C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial humeral head surface
element constructed and operative in accordance with still another
preferred embodiment of the present invention.
[0448] As seen in FIGS. 24A, 24B and 24C, an implantable artificial
humeral head surface element, designated by reference numeral 3400,
is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0449] Preferably, implantable artificial humeral head surface
element 3400 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about an axis 3401 and
defines an articulation surface 3402, which defines a portion of a
convex spherical surface, and a bone engagement surface 3404,
having a beveled edge 3405, which preferably has formed thereon, at
any suitable location between its apex and its rim, a generally
annular outwardly extending array 3406 of discrete recesses 3407,
preferably defining a generally annular array 3408 of undercuts
3409. Alternatively, the array 3406 may be any other suitable
non-annular, open or closed, generally peripheral, array of
recesses. The array 3406 of recesses 3407 is preferably arranged
for snap-fit engagement with corresponding protrusions formed inter
alia by suitable machining of a humeral head.
[0450] Preferably, the recesses 3407 have a generally button-like
configuration which is symmetric about an axis 3410 and include a
body portion 3411 and an enlarged head portion 3412, as can be
readily seen in FIG. 24B. Recesses 3407 are generally characterized
in that an overlying surface portion 3413 of each recess 3407
defines peripheral undercut 3409 with respect to axis 3410.
[0451] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
humeral head surface element 3400 at the apex thereof, any suitable
portion thereof may be of non-uniform thickness.
[0452] Reference is now made to FIGS. 25A and 25B, which are
respective exploded view and assembled view illustrations of the
implantable artificial glenoid socket of FIGS. 15A-15C in a total
shoulder replacement environment. As seen in FIGS. 25A and 25B,
implantable artificial glenoid socket 2500 (FIGS. 15A-15C) is
snap-fitted into a suitably machined natural glenoid of a patient.
A conventional artificial humeral head 3500 is mounted onto a
conventional humeral stem 3502 and is arranged for articulation
with articulation surface 2502 of socket 2500.
[0453] Reference is now made to FIGS. 26A and 26B, which are
respective exploded view and assembled view illustrations of the
implantable artificial glenoid socket of FIGS. 15A-15C in a partial
shoulder replacement environment. As seen in FIGS. 26A and 26B,
implantable artificial glenoid socket 2500 (FIGS. 15A-15C) is
snap-fitted into a suitably machined natural glenoid of a patient.
A natural humeral head 3600 is arranged for articulation with
articulation surface 2502 of socket 2500.
[0454] It is a particular feature of the embodiment of FIGS. 26A
and 26B that the size and configuration of articulation surface
2502 of artificial glenoid socket 2500 is made to be identical to
that of the natural glenoid socket of the patient, in order that
the natural humeral head 3600 may articulate therewith with desired
dimensional clearances and without requiring machining of the
humeral head. The ability of the articulation surface 2502 of
socket 2500 to be identical to that of the natural humeral head is
provided by the flexibility and resiliency of artificial glenoid
socket 2500, which enables small adjustments in the size and
configuration of the articulation surface 2502 to be realized by
suitably exact machining of the natural glenoid socket.
[0455] Reference is now made to FIGS. 27A and 27B, which are
respective exploded view and assembled view illustrations of the
implantable artificial humeral head surface element of FIGS.
20A-20C in a hemi shoulder resurfacing environment. As seen in
FIGS. 27A and 27B, a suitably machined natural humeral head 3650
having the implantable artificial humeral head surface element 3000
of FIGS. 20A-20C snap-fit mounted thereon is arranged for
articulation of articulation surface 3002 thereof with a natural
articulation surface 3652 of a natural glenoid.
[0456] It is a particular feature of the embodiment of FIGS. 27A
and 27B that the size and configuration of articulation surface
3002 of artificial humeral head surface element 3000 is made to be
identical to that of the natural glenoid socket 3652 of the
patient, in order that the natural humeral head 3650 onto which
artificial humeral head surface element 3000 is mounted may
articulate therewith with desired dimensional clearances and
without requiring machining of the natural glenoid. The ability of
the articulation surface 3002 of humeral head surface element 3000
to be identical to that of the natural glenoid is provided by the
flexibility and resiliency of artificial humeral head surface
element 3000, which enables small adjustments in the size and
configuration of the articulation surface 3002 to be realized by
suitably exact machining of the humeral head.
[0457] Reference is now made to FIGS. 28A and 28B, which are
respective exploded view and assembled view illustrations of the
implantable artificial glenoid socket of FIGS. 15A-15C and the
implantable artificial humeral head surface element of FIGS.
20A-20C in a total shoulder resurfacing environment. As seen in
FIGS. 28A and 28B, implantable artificial glenoid socket 2500
(FIGS. 15A-15C) is snap-fitted into a suitably machined natural
glenoid of a patient. A suitably machined natural humeral head 3700
having the implantable artificial humeral head surface element 3000
of FIGS. 20A-20C snap-fit mounted thereon is arranged for
articulation of articulation surface 3002 thereof with articulation
surface 2502 of socket 2500.
[0458] Reference is now made to FIGS. 29A and 29B, which are
pictorial illustrations showing an implantable artificial medial
meniscus implant assembly constructed and operative in accordance
with a preferred embodiment of the present invention. As seen in
FIGS. 29A and 29B, an implantable artificial medial meniscus
implant assembly, designated by reference numeral 4060, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0459] Preferably, implantable meniscus implant assembly 4060
defines a concave articulation surface 4061, which is defined on an
articulation portion 4063, a convex articulation surface 4064,
which is defined on an articulation portion 4065, and a bone
snap-fit engagement element 4066 for locking engagement with a
matching machined tibia recess (not shown) which is defined on a
bone anchoring portion 4067. Articulation portion 4063 preferably
has formed thereon multiple protrusions 4068 for snap-fit
engagement with multiple recesses 4069 defined on articulation
portion 4065.
[0460] Articulation portions 4063 and 4065 may alternatively be
formed as one piece constructed to fold and snap-fit on itself,
only in some portions of the snap-fit engagement regions provided
in assembly 4060.
[0461] Articulation portion 4063 has formed, in articulation
surface 4061, a plurality of thoroughgoing apertures 4070, which,
as described hereinbelow, allow synovial fluid to pass therethrough
for lubrication of the articulation surface 4061 when articulation
portion 4063 articulates with the articulation surface of the
femur. Articulation portion 4065 has formed in articulation surface
4064 a plurality of thoroughgoing apertures 4071, which, as
described hereinbelow, allow synovial fluid to pass therethrough
for lubrication of the articulation surface 4064 when articulation
portion 4065 articulates with the articulation surface of the
tibia.
[0462] The application of force on articulation surface 4061 or
articulation surface 4064 causes the corresponding articulation
portion 4063 or 4065 to be resiliently displaced inwardly, thus
causing synovial fluid, located between the articulation portion
4063 and the articulation portion 4065 to be forced through
apertures 4070 and 4071 so as to lie on and over articulation
surfaces 4061 or 4064 and to provide enhanced lubrication for the
articulation of articulation surfaces 4061 and 4064.
[0463] In accordance with a preferred embodiment of the present
invention, in addition to the snap-fit anchoring to the tibia by
element 4066, implantable meniscus implant assembly 4060 is also
securely positioned into a sliding operational condition with
respect to any of femur articulating surface and tibia articulating
surface by multiple tissue secure assemblies 4074.
[0464] As seen in FIG. 29A, insert elements 4076 are securely
assembled between articulation portion 4063 and articulation
portion 4065. As seen in FIG. 29B, insert elements 4076 are formed
on each end of clip 4077 shown gripping from the outside a
connecting tissue fraction 4078 of the connecting tissue
surrounding the knee joint.
[0465] Implantable meniscus implant assembly 4060 also comprises an
inner grip element 4079, shown in FIG. 29B gripping the connecting
tissue fraction 4078 from the inside. Tissue secure assembly 4074
defines a rounded edge seat 4080 provided for slidingly securing
the tissue fraction 4078 with respect to the tissue secure assembly
4074. A first segment of seat 4080 is formed as a recess on the
inside surface of clip 4077 and a second segment of seat 4080 is
formed as a recess on the outside surface of grip 4079.
[0466] Reference is now made to FIGS. 30A and 30B, which are
pictorial illustrations of a pre installation stage of an
implantable artificial patella surface element, constructed and
operative in accordance with a preferred embodiment of the present
invention. FIG. 30A shows an implantable artificial patella surface
element 4100, while FIG. 30B illustrates the preparation of the
patella for implantation of implantable artificial patella surface
element 4100. As seen in FIG. 30A, implantable artificial patella
surface element 4100 is formed, preferably, by injection molding of
polyurethane. Preferred polyurethane materials are described
hereinbelow.
[0467] Preferably, implantable artificial patella surface element
4100 defines a concave articulation surface 4102 and an outer
peripheral protrusion 4104 arranged for snap-fit engagement with a
corresponding recess 4106 provided by machining of patella 4110.
Implantable artificial patella surface element 4100 also preferably
includes a plurality of thoroughgoing apertures 4108 to allow
synovial fluid to pass therethrough for lubrication of the
articulation surface 4102, as described hereinbelow with reference
to FIG. 32B.
[0468] As seen in FIG. 30B, recess 4106 is formed with an inner
circumferential undercut 4112. A planar surface 4114, an undercut
closed circumferential groove 4116 and an additional planar surface
4117 are provided by machining of the patella 4110.
[0469] Reference is now made to FIGS. 31A, 31B and 31C, which show
artificial patella surface element 4100 of FIG. 30A installed in a
patella 4110, prepared as shown in FIG. 30B, in accordance with a
preferred embodiment of the present invention. As seen in FIG. 31B,
outer peripheral protrusion 4104 of implantable artificial patella
surface element 4100 defines an undercut 4120 configured for a
snap-fit engagement with undercut 4112 machined in recess 4106 in
patella 4110. In addition, artificial patella surface element 4100
defines an inner snap-fit circumferential locking portion 4115
comprising undercut 4122 configured for a snap-fit engagement with
groove 4116 machined in patella 4110. It is appreciated that
artificial patella surface element 4100 is configured with an inner
free surface 4124 positioned remote from planar surface 4117
creating a void 4126. Articulating portion 4130 of artificial
patella surface element 4100 is external to inner free surface 4124
and is defined by circumferential snap-fit locking portion 4115.
Articulating portion 4130 of artificial patella surface element
4100 also preferably includes apertures 4108 to allow synovial
fluid to pass therethrough for lubrication of the articulation
surface 4102, as described hereinbelow with reference to FIG.
32B.
[0470] Reference is now made to FIGS. 32A and 32B, which are
sectional illustrations of the implantable artificial patella
surface element 4100 of FIG. 30A in a patella replacement
environment in operative orientations where the joint is
un-impacted and wherein the joint is impacted.
[0471] In FIG. 32A, which shows an un-impacted joint, patella 4110
and artificial patella surface element 4100 are installed in an
articulating arrangement with lateral condyle 4140, medial condyle
4141 and trochlear groove 4142. The approximate center of
articulation of the femur is shown as an axis 4143, and the
approximate center of articulation of the articulating portion 4130
of artificial patella surface element 4100 is shown as an axis
4144. Most of the articulating contact of artificial patella
surface element 4100 is performed by articulation portion 4130,
providing a space 4146 between patella 4110 and lateral condyle
4140 and a space 4148 between patella 4110 and medial condyle
4141.
[0472] Articulating portion 4130 may undergo deformation when
frontal impact force is exerted on patella 4110. An example of such
impact force is the impact force here designated by arrow 4150.
This frontal impact force results in an inward deformation of
articulation portion 4130, thus providing a shock-absorbing effect
protecting the joint from being damaged by the impact force.
[0473] FIG. 32B shows the joint being impacted by a lateral impact
force, designated here by arrow 4152, exerted on artificial patella
surface element 4100. The lateral impact force deflects patella
4110 sideways in relation to the femoral condyles as can be seen
from the shifted position of axis 4144 in relation to axis 4143.
The flexible construction of articulating portion 4130 allows a
considerable deformation from its original form without dislodgment
of artificial patella surface element 4100 from its anchoring
engagement with patella 4110. The deformation of articulating
portion 4130 results in recoil energy which returns the patella
4110 to its original orientation after the impact force
dissipates.
[0474] In accordance with a preferred embodiment of the present
invention, articulating portion 4130 includes apertures 4108 (FIG.
31A) to allow synovial fluid to pass therethrough for lubrication
of the articulation surface 4102.
[0475] At least part of articulation portion 4130 is forced to be
resiliently displaced toward any of lateral condyle 4140, medial
condyle 4141 and trochlear groove 4142, laterally by any of frontal
impact force, lateral impact force, flexation action of the knee
joint and extension action of the knee joint. Such resilient
displacement causes synovial fluid, located in void 4126, to be
forced through apertures 4108 (FIG. 31A) so as to lie on and over
articulation surface 4102 and to provide enhanced lubrication for
the articulation of articulation surface 4102 of articulation
portion 4130 with the femoral condyles 4140 and 4141 and trochlear
groove 4142.
[0476] Reference is now made to FIGS. 33A, 33B, 33C, 33D, 33E and
33F, which are simplified illustrations of first and second
implantable artificial humeral elbow surface elements, constructed
and operative in accordance with another preferred embodiment of
the present invention, which are particularly useful for an elbow
joint.
[0477] As seen in FIGS. 33A, 33B, 33D and 33E, an artificial
humeral elbow surface element 4180 is constructed for articulation
with the ulna and an artificial humeral surface element 4182 is
constructed for articulation with the radius. Implantable
artificial humeral surface elements 4180 and 4182 are formed,
preferably, by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0478] Preferably, implantable artificial humeral surface elements
4180 and 4182 are of generally uniform thickness, and define,
respectively, an articulation surface 4184, which defines a portion
of a concave saddle shape surface, and an articulation surface
4186, which defines a portion of a convex generally spherical
surface, and respective bone engagement surfaces 4188 and 4190.
Bone engagement surfaces 4188 and 4190 preferably have formed
thereon respective peripheral protrusion elements 4192 and
4194.
[0479] As seen in FIGS. 33C and 33F, peripheral protrusion elements
4192 and 4194 define respective undercuts 4196 and 4198.
Alternatively, protrusions elements 4192 and 4194 may be any other
suitable open or closed protrusions. Protrusions 4192 and 4194 are
preferably arranged for snap-fit engagement with corresponding
grooves formed by machining of the humerus.
[0480] Reference is now made to FIGS. 34A, 34B, 34C, 34D, 34E and
34F, which are simplified illustrations of an implantable
artificial ulna surface element and an implantable radius surface
element, constructed and operative in accordance with another
preferred embodiment of the present invention, which are
particularly useful for an elbow joint. As seen in FIGS. 34A, 34B,
34C, 34D, 34E and 34F, artificial ulna surface element 4210 and
artificial radius surface elements 4212 are constructed for
articulation with the humerus. Implantable artificial ulna surface
element 4210 and artificial radius surface element 4212 are formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0481] Preferably, implantable artificial ulna surface element 4210
and artificial radius surface elements 4212 are of generally
uniform thickness and respectively define an articulation surface
4214, which defines a portion of a concave saddle shape surface,
and an articulation surface 4216, which defines a portion of a
concave generally spherical surface, and respective bone engagement
surfaces 4218 and 4220. Bone engagement surfaces 4218 and 4220
preferably have formed thereon respective peripheral protrusion
elements 4226 and 4228. Peripheral protrusion elements 4226 and
4228 define respective undercuts 4232 and 4234. Alternatively,
protrusions elements 4226 and 4228 may be any other suitable, open
or closed protrusions. Protrusions 4226 and 4228 are preferably
arranged for snap-fit engagement with corresponding grooves formed
by machining of the ulna and radius, respectively.
[0482] Reference is now made to FIGS. 35A and 35B, which are
respective exploded view and assembled view illustrations of the
implantable artificial humeral elbow elements of FIGS. 33A-33F in a
partial elbow replacement environment. FIG. 35A shows a pre
installation stage, while FIG. 35B shows the elements
installed.
[0483] As seen in FIG. 35A, protrusion 4192 of implantable
artificial humeral elbow element 4180 is preferably arranged for
snap-fit engagement with corresponding groove 4242 formed by
machining of the humerus. Groove 4242 is preferably formed with an
undercut 4244 matching undercut 4196 of protrusion 4192.
[0484] Protrusion 4194 of implantable artificial humeral elbow
element 4182 is preferably arranged for snap-fit engagement with
corresponding groove 4246 formed by machining of the humerus.
Groove 4246 is preferably formed with an undercut 4248 matching
undercut 4198 of protrusion 4194.
[0485] FIG. 35B shows implantable artificial humeral elbow element
4180 and implantable artificial humeral elbow element 4182 mounted
onto a humerus.
[0486] Reference is now made to FIGS. 36A and 36B, which are
respective exploded view and assembled view illustrations of the
implantable artificial ulna surface element 4210 and artificial
radius surface elements 4212 of FIGS. 34A-34F in a partial elbow
replacement environment. FIG. 36A shows a pre installation stage,
while FIG. 36B shows the elements installed.
[0487] As seen in FIG. 36A, protrusion 4226 of implantable
artificial ulna surface element 4210 is preferably arranged for
snap-fit engagement with a corresponding groove 4252 formed by
machining of the ulna. Groove 4252 is preferably formed with an
undercut 4254 matching undercut 4232 of protrusion 4226.
[0488] Protrusion 4228 of artificial radius surface element 4212 is
preferably arranged for snap-fit engagement with a corresponding
groove 4256 formed by machining of the radius. Groove 4256 is
preferably formed with an undercut 4258 matching undercut 4234 of
protrusion 4228.
[0489] FIG. 36B shows implantable artificial ulna elbow element
4210 mounted onto an ulna and implantable artificial radius elbow
element 4212 mounted onto a radius
[0490] Reference is now made to FIG. 37, which is a simplified
illustration of the implantable humeral elbow elements of FIGS.
33A-33F and the implantable artificial ulna and radius elements of
FIGS. 34A-34F in a total elbow replacement environment.
[0491] As seen in FIG. 37, implantable artificial humeral elbow
element 4180 and implantable artificial humeral elbow element 4182
are shown mounted onto a humerus. Implantable artificial ulna elbow
element 4210 is shown mounted onto an ulna and implantable
artificial radius elbow element 4212 is shown mounted onto a
radius.
[0492] Articulation surface 4184 of artificial humeral elbow
element 4180 articulates with articulation surface 4214 of
artificial ulna elbow element 4210. Articulation surface 4186 of
artificial humeral elbow element 4182 articulates with Articulation
surface 4216 of artificial radius elbow element 4212.
[0493] Reference is now made to FIGS. 38A, 38B, 38C and 38D, which
illustrate a groove reaming tool constructed and operative in
accordance with a preferred embodiment of the present invention. As
seen in FIGS. 38A and 38B, a hand operated reaming tool 4800 is
provided with a handle 4802, fixedly coupled to a shaft 4804. An
elongate grip 4806 is rotatably and slidably mounted over shaft
4804 and axially engages an outwardly extendible recess engagement
element 4808, which is also rotatably and slidably mounted with
respect to shaft 4804.
[0494] Outwardly extendible recess engagement element 4808 is
preferably an integrally formed element made of metal, such as
spring steel, and includes a generally hollow cylindrical portion
4810 formed with a plurality of axially extending slots 4812, which
extend from a location spaced from a top edge 4814 of the
cylindrical portion 4810 towards and through a generally radially
outwardly extending disk-like portion 4816.
[0495] It is appreciated that disk-like portion 4816 thus includes
a plurality of azimuthally separated segments 4818, each of which
defines a continuation of a corresponding azimuthally separated
segment 4820 of cylindrical portion 4810. Preferably, an outer edge
4822 of disk-like portion 4816 is formed with a high friction
engagement surface, such as a toothed surface.
[0496] It is seen that preferably disk-like portion 4816 is formed
with a central generally conical recess 4824 on an underside
surface 4826 thereof.
[0497] A generally solid, centrally apertured conical element 4830
is rotatably mounted onto shaft 4804 such that a conical surface
4832 thereof is adapted to operatively enrage conical recess 4824
in a manner that such engagement produces radially outward
displacement of segments 4818 of disk-like portion 4816.
[0498] Preferably, there is provided a retainer element 4840 which
is rotatably mounted with respect to shaft 4804 and overlies
disk-like portion 4816. Preferably retainer element 4840 includes
depending plates 4842 which engage interstices between segments
4818.
[0499] In accordance with a preferred embodiment of the invention,
a groove cutter mounting element 4850 is fixedly mounted to shaft
4804 for rotation together therewith in response to rotation of
handle 4802. Groove cutter mounting element 4850 preferably
underlies conical element 4830 and is separated therefrom by a
washer 4852, to enable groove cutter mounting element 4850 to
easily rotate with respect to conical element 4830.
[0500] An end element 4860 is rotatably mounted onto an end of
shaft 4804, underlying groove cutter mounting element 4850 such
that groove cutter mounting element 4850 is rotatable with respect
thereto. End element 4860 is preferably formed with a high friction
engagement surface 4862, such as a toothed surface, on the
underside thereof.
[0501] Groove cutter mounting element 4850 is preferably a
generally hollow hemispherical element having a central hub 4864
which defines a rectangular thoroughgoing aperture 4866 for
receiving an end 4868 of shaft 4804. Three extending recesses 4869,
4870 and 4871, respectively, are formed in an outer facing wall
4872 of hub 4864. A corresponding generally elongate aperture 4874
is formed in a wall 4875 of groove cutter mounting element 4850
opposite recesses 4869, 4870 and 4871. Aperture 4874 extends
azimuthally beyond recesses 4869, 4870 and 4871.
[0502] A plurality of cutter elements 4880, preferably three in
number, are together removably retained in groove cutter mounting
element 4850. As seen clearly in FIGS. 38C and 38D, the cutter
elements 4880 are preferably of similar configuration, but have at
least one differing dimension. Each cutter element 4880 preferably
is formed of a flat piece of metal and includes a hook portion
4882, defining an undercut 4884, a central portion 4886 and a
cutting portion 4888, which defines a curved cutting edge 4890
inwardly of which is defined an aperture 4892 having a beveled
peripheral edge 4894.
[0503] Preferably, as seen clearly in FIG. 38D, the cutter elements
4880 are arranged such that their hook portions 4882 engage
recesses 4869, 4870 and 4871 and their cutting portions 4888 extend
outwardly of wall 4875 through aperture 4874. Preferably the extent
of central portions 4886 of cutter elements 4880 varies such that
the amount that cutting portions 4888 extend outwardly of wall 4875
varies as illustrated in FIG. 38D. Preferably, the cutting elements
4880 are arranged to provide a stepped increase in the extent that
the cutting portions 4888 extend outwardly, in the direction of
operational rotation of the tool 4800.
[0504] Reference is now made to FIGS. 39A and 39B, which are
illustrations of another portion of the groove reaming tool of
FIGS. 38A and 38B in first and second operative orientations. In a
first, non-engagement orientation shown in FIG. 39A, when grip 4806
is not pushed downward along shaft 4804 towards groove cutter
mounting element 4850 (FIGS. 38A and 38B), outwardly extendible
recess engagement element 4808 is not subject to downward axial
force and thus no axial force is applied between recess 4824, on
the underside surface 4826 thereof, and conical element 4830.
[0505] In a second, bone recess engagement orientation shown in
FIG. 39B, grip 4806 is pushed downward along shaft 4804 towards
groove cutter mounting element 4850 (FIGS. 38A and 38B), as
indicated by an arrow 4896 and engages outwardly extendible recess
engagement element 4808, forcing recess 4824 on the underside
surface 4826 thereof axially against conical element 4830, as
indicated by arrow 4897. This axial force causes radially outward
displacement of segments 4818 of disk-like portion 4816, as
indicated by arrow 4898.
[0506] Reference is now made to FIGS. 40A-40G, which illustrate
various stages in groove reaming of an acetabulum in accordance
with a preferred embodiment of the present invention preferably
employing the apparatus of FIGS. 38A-38D.
[0507] FIG. 40A illustrates groove reaming tool 4800 prior to
engagement with an acetabulum which has been previously reamed. It
is seen that the cutting portions 4888 of cutter elements 4880 are
aligned with an acetabulum notch 5000 and that the shaft 4804 is
arranged along an axis 5002 which is approximately coaxial with the
axis of symmetry of the reamed acetabulum 5004, which axis of
symmetry is designated by reference numeral 5006.
[0508] FIG. 40B illustrates the groove reaming tool 4800 following
insertion thereof via notch 5000, wherein cutting portions 4888 of
cutter elements 4880 are still located within acetabulum notch
5000. The groove reaming tool 4800 is also shown fully aligned with
axis of symmetry 5006.
[0509] FIG. 40C illustrates the groove reaming tool 4800 following
application of axial downward force, as indicated by an arrow 5007
on handle 4802, causing high friction engagement surface 4862 of
end element 4860 to frictionally engage the reamed acetabulum
5004.
[0510] FIG. 40D shows the groove reaming tool 4800 following
application of axial downward force, as indicated by an arrow 5009
on grip 4806, causing grip 4806 to engage outwardly extendible
recess engagement element 4808 with linear force 5010, thereby
forcing the recess on the underside surface thereof axially against
the conical element, as illustrated in FIG. 39B at arrow 4897. This
axial force causes radially outward displacement of segments 4818
and causes the high friction surface on the outer edge 4822 of
segments 4818 into frictional engagement with the reamed acetabulum
5004, as indicated by arrow 5012.
[0511] FIG. 40E shows the groove reaming tool 4800 following an
approximately 180 degree rotation of handle 4802, groove cutter
mounting element 4850 and cutter elements 4880 about coaxial axes
5002 and 5006, as indicated by arrow 5014, thereby producing an
approximately 180 degree groove 5016 (seen in FIG. 40G) in reamed
acetabulum 5004.
[0512] FIG. 40F shows the groove reaming tool 4800 following a
further approximately 180 degree rotation of handle 4802, groove
cutter mounting element 4850 and cutter elements 4880 about coaxial
axes 5002 and 5006, as indicated by arrow 5018, thereby extending
groove 5016, producing a 360 degree groove in reamed acetabulum
5004.
[0513] FIG. 40G illustrates the groove reaming tool 4800 following
removal thereof via notch 5000, wherein cutting portions 4888 of
cutter elements 4880 are still aligned with the acetabulum notch
5000, showing groove 5016 produced in the steps described in FIGS.
40E and 40F.
[0514] Reference is now made to FIGS. 41A, 41B, 41C and 41D, which
are sectional illustrations, showing alternative reamed acetabulum
configurations.
[0515] FIG. 41A illustrates a modification of the machined
acetabulum shown in FIG. 40G, wherein a discontinuous groove array
5100 is shown. This groove array is preferably configured to
correspond with the protrusion array shown in FIG. 2A.
[0516] FIG. 41B illustrates another modification of the machined
acetabulum shown in FIG. 40G, wherein another type of discontinuous
recess array 5102 is shown. This groove array is preferably
configured to correspond with the protrusion array shown in FIG.
3A.
[0517] FIG. 41C illustrates another modification of the machined
acetabulum shown in FIG. 40G, wherein a circumferential protrusion
5104 is shown. This circumferential protrusion is preferably
configured to correspond with the circumferential recess shown in
FIG. 4A.
[0518] FIG. 41D illustrates another modification of the machined
acetabulum shown in FIG. 40G, wherein a discontinuous protrusion
array 5106 is shown. This discontinuous protrusion array 5106 is
preferably configured to correspond with recess array shown in FIG.
5A.
[0519] Reference is now made to FIGS. 42A and 42B, which are
simplified pictorial illustrations of introduction and pre-snap fit
placement of an implantable artificial femoral head resurfacing
element adjacent a reamed femoral head in accordance with two
alternative embodiments of the present invention. FIG. 42A shows
introduction and placement of an implantable artificial femoral
head resurfacing element 5150 adjacent a reamed femoral head 5152.
Implantable artificial femoral head resurfacing element 5150 may be
any suitable implantable artificial femoral head resurfacing
element such as those shown and described herein, for example, in
any of FIGS. 6A-10C.
[0520] FIG. 42B shows introduction and placement of a folded
implantable artificial femoral head resurfacing element 5160
adjacent a reamed femoral head 5162. Implantable artificial femoral
head resurfacing element 5160 may be any suitable implantable
artificial femoral head resurfacing element such as those shown and
described herein, for example in any of FIGS. 6A-10C. The
embodiment of FIG. 42B is particularly suitable for minimally
invasive surgery.
[0521] Reference is now made to FIGS. 43A and 43B, which are
simplified pictorial illustrations of introduction and pre-snap fit
placement of an implantable artificial acetabular socket adjacent a
reamed acetabulum in accordance with two alternative embodiments of
the present invention. FIG. 43A shows introduction and placement of
an implantable artificial acetabular socket 5170 adjacent a reamed
acetabulum 5172. Implantable artificial acetabular socket 5170 may
be any suitable implantable artificial acetabular socket such as
those shown and described herein, for example in any of FIGS.
1A-5C.
[0522] FIG. 43B shows introduction and placement of a folded
implantable artificial acetabular socket 5180 adjacent a reamed
acetabulum 5182. Implantable artificial acetabular socket 5180 may
be any suitable implantable artificial acetabular socket such as
those shown and described herein, for example in any of FIGS.
1A-5C. The embodiment of FIG. 43B is particularly suitable for
minimally invasive surgery.
[0523] Reference is now made to FIGS. 44A, 44B, 44C and 44D, which
are, respectively, a simplified pictorial illustration and
sectional illustrations of a snap-fit installation of an
implantable artificial acetabular socket in a reamed acetabulum in
accordance with a preferred embodiment of the present invention. As
shown in FIG. 44A, following introduction and placement of an
implantable artificial acetabular socket adjacent a reamed
acetabulum, a surgeon, using his fingers, gently introduces the
artificial acetabular socket into position for snap-fit engagement
with the reamed acetabulum. This position is shown clearly in FIG.
44B, which is a sectional illustration of the reamed acetabulum of
FIG. 44A.
[0524] For the sake of conciseness and clarity, the implantable
artificial acetabular socket 1100 of FIGS. 1A-1C and the
description thereof are employed in the explanation which follows,
unless specifically indicated otherwise. It is appreciated,
however, that where suitable, any other type of acetabular socket
described herein may be installed in a manner employing features
described hereinbelow.
[0525] At the positioning stage shown in FIGS. 44A and 44B, annular
outwardly extending protrusion 1106 lies in touching, generally
non-compressive engagement with an annular portion 5200 of a
generally spherical inner concave surface 5202 of a machined
acetabulum 5204. Annular portion 5200 lies above a groove 5206,
formed in generally spherical inner concave surface 5202, which is
designed to receive protrusion 1106. Accordingly, engagement of
protrusion 1106 with annular portion 5200 causes the implantable
artificial acetabular socket 1100 to rest at a position wherein an
outer edge thereof, designated by reference numeral 5210, lies
above a corresponding outer edge 5212 of machined acetabulum 5204.
The separation between the planes of outer edge 5210 of implantable
artificial acetabular socket 1100 and of outer edge 5212, along
axis 1101, is indicated by arrows 5214.
[0526] As can be seen from FIG. 44B, substantially no stress is
applied to the implantable artificial acetabular socket 1100 and to
machined acetabulum 5204 by the engagement thereof shown in FIGS.
44A and 44B.
[0527] FIG. 44C illustrates a second stage in snap-fit installation
of an implantable artificial acetabular socket in a reamed
acetabulum in accordance with a preferred embodiment of the present
invention. As shown in FIG. 44C, following placement of implantable
artificial acetabular socket 1100 into position for snap-fit
engagement with the reamed acetabulum, as shown in FIGS. 44A and
44B, the surgeon, using his fingers, gently engages the artificial
acetabular socket 1100, preferably at locations, designated by
reference numeral 5220, on inner concave surface 1102 thereof, and
presses thereon in a direction indicated by arrows 5222, which
direction lies generally along axis 1101. The application of this
pressure causes displacement of artificial acetabular socket 1100
in direction 5222. Due to the concave configuration of surface 5202
at annular surface portion 5200, this displacement produces
radially inward compression of artificial acetabular socket 1100 at
protrusion 1106, as indicated by arrows 5224 This radially inward
compression results in deformation of the artificial acetabular
socket 1100 at protrusion 1106 and in the general region thereof,
as indicated, inter alia by arrows 5226.
[0528] The radially inward compression and the resulting
deformation of artificial acetabular socket 1100 produces stresses
in the acetabular socket 1100, as illustrated, inter alia, by
stress contour lines 5231, 5232, 5233 and 5234. The above-described
engagement of artificial acetabular socket 1100 with the machined
acetabulum 5204 causes forces to be applied to the machined
acetabulum 5204, producing compression stresses therein, as
illustrated, inter alia, by stress contour lines 5241, 5242, 5243
and 5244, in a region designated by reference numeral 5246, in the
vicinity of annular surface portion 5200. It is appreciated that
the stresses thus produced in machined acetabular socket 5204
produce corresponding strains therein. Both the stresses and the
strains have positive medical implications, as will be discussed
hereinbelow.
[0529] Displacement of artificial acetabular socket 1100 in
direction 5222 is seen to reduce the separation between the planes
of outer edge 5210 of implantable artificial acetabular socket 1100
and of outer edge 5212 along axis 1101, indicated by arrows
5254.
[0530] FIG. 44D illustrates a third stage in snap-fit installation
of an implantable artificial socket in a reamed acetabulum in
accordance with a preferred embodiment of the present invention. As
shown in FIG. 44D, the surgeon, using his fingers, presses further
on the artificial acetabular socket 1100 preferably at locations,
designated by reference numeral 5220 on inner concave surface 1102
thereof in the direction indicated by arrows 5222. The application
of this further pressure, causes further displacement of artificial
acetabular socket 1100 in direction 5222. This further displacement
produces sliding pressure engagement between underlying surface
portion 1110 of protrusion 1106 at the undercut 1108 and a radially
outward extending surface portion 5260 of groove 5206. It is noted
that the resiliency of the artificial acetabular socket 1100 causes
radially outward displacement of protrusion 1106, as indicated by
arrows 5262. The resulting radially outward decompression results
in different deformation of the artificial acetabular socket 1100
at protrusion 1106 and in the general region thereof, as indicated,
inter alia by arrow 5266.
[0531] This results in reduced and changed stress patterns in both
the artificial acetabular socket 1100 and in the machined
acetabulum 5204 at region 5246 thereof, as indicated by stress
contour lines 5271, 5272, 5273 and 5274 in artificial acetabular
socket 1100 and by stress contour lines 5281, 5282, 5283 and 5284
in machined acetabulum 5204.
[0532] The further displacement of artificial acetabular socket
1100 in direction 5222 is seen to further reduce the separation
between the planes of outer edge 5210 of implantable artificial
acetabular socket 1100 and of outer edge 5212 along axis 1101,
indicated by arrows 5294.
[0533] Reference is now made to FIGS. 45A and 45B, which are a
simplified pictorial illustration and sectional illustration of a
fourth stage in snap-fit installation of an implantable artificial
acetabular socket in a reamed acetabulum in accordance with a
preferred embodiment of the present invention. As shown in FIG.
45A, the surgeon, using his fingers, now presses on the artificial
acetabular socket 1100, preferably at locations, designated by
reference numeral 5300, on edges 5210 thereof, in the direction
indicated by arrow 5222.
[0534] As seen in FIG. 45B, the application of this further
pressure causes further displacement of artificial acetabular
socket 1100 in direction 5222. This further displacement produces
sliding snap-fit engagement between protrusion 1106 and groove
5206.
[0535] It is noted that the resiliency of the artificial acetabular
socket 1100 causes radially outward displacement of protrusion
1106, as indicated by arrows 5302. The resulting radially outward
decompression generally eliminates deformation of the artificial
acetabular socket 1100 at protrusion 1106 and in the general region
thereof designated by reference numeral 5220.
[0536] It is noted that the snap-fit engagement shown in FIG. 45B
is a generally non-press fit engagement. Touching engagement
between the artificial acetabular socket 1100 and the machined
acetabulum 5204 typically takes place at surface 1104 of artificial
acetabular socket 1100 and surface 5202 of the machined acetabulum.
Accordingly the stresses in both the acetabular socket 1100 and in
the machined acetabulum 5204 are generally small and localized in
the region of the snap fit engagement therebetween, as indicated by
stress contour lines 5311 and 5312 in artificial acetabular socket
1100 and by stress contour lines 5321 and 5322 in machined
acetabulum 5204.
[0537] It is also appreciated that the snap-fit engagement of the
artificial acetabular socket 1100 with the machined acetabulum 5204
produces locking of the artificial acetabular socket 1100 in groove
5206, wherein undercut 1108 prevents disengagement of protrusion
1106 from groove 5206.
[0538] Reference is now made to FIGS. 46A, 46B, 46C and 46D, which
are illustrations of an implantable artificial acetabular socket,
constructed and operative in accordance with a further preferred
embodiment of the present invention, which is particularly suitable
for use in a hip joint.
[0539] As seen in FIGS. 46A, 46B, 46C and 46D, an implantable
artificial acetabular socket, designated by reference numeral 5600,
is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0540] Preferably, implantable artificial acetabular socket 5600 is
of an uneven thickness, and defines a concave hemispherical inner
articulation surface 5602 which is symmetric about an axis 5601,
having a beveled edge 5603, and a generally hemispherical outer
bone engagement surface 5604 which preferably has formed thereon at
any suitable location between its apex and its rim a generally
annular outwardly extending protrusion 5606, preferably defining a
generally annular undercut 5608. Alternatively, the protrusion 5606
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 5606 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0541] Preferably, the protrusion 5606 has a cross-sectional
configuration, as can be readily seen in FIG. 46B, which is
characterized in that an underlying surface portion 5610 of
protrusion 5606, at the undercut 5608, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
5612 of protrusion 5606.
[0542] It is a particular feature of the implantable artificial
acetabular socket 5600 that its thickness varies at various
regions, corresponding to various portions of the bone engagement
surface 5604, which gives it an asymmetric configuration requiring
a definition of the implanting orientation with regard to the
acetabulum. Preferably, a marking 5620, such as a writing "notch"
corresponding to the acetabulum notch, is used to position
implantable artificial acetabular socket 5600 in its designed
orientation by placing the marking 5620 at the acetabulum
notch.
[0543] Preferably, implantable artificial acetabular socket 5600
defines an uneven thickness portion 5626 between its apex and the
annular outwardly extending protrusion 5606. Alternatively, other
uneven thickness portions may be defined, such as a protrusion
similar to protrusion 5606 constructed of a varied cross section.
Alternatively, the portion defined between annular outwardly
extending protrusion 5606 and the rim may be of an uneven
thickness.
[0544] As seen in FIG. 46B, which is a sectional illustration taken
along lines XLVIB-XLVIB of FIG. 46A, preferably, uneven thickness
portion 5626 includes a region 5628 of a thickness less than the
average thickness of uneven thickness portion 5626, which is
located opposite marking 5620, which is at the bottom part of
implantable artificial acetabular socket 5600, and a region 5630 of
a thickness greater than the average thickness of uneven thickness
portion 5626, located towards marking 5620 at the bottom part of
the implantable artificial acetabular socket 5600.
[0545] As seen in FIG. 46C, which is a sectional illustration taken
along lines XLVIC-XLVIC of FIG. 46A, uneven thickness portion 5626
may include other variations of thickness across uneven thickness
portion 5626.
[0546] Reference is now made to FIGS. 47A, 47B and 47C, which are
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with another preferred
embodiment of the present invention, which is particularly suitable
for use in a hip joint.
[0547] As seen in FIGS. 47A, 47B and 47C, an implantable artificial
acetabular socket, designated by reference numeral 5640, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0548] Preferably, implantable artificial acetabular socket 5640 is
of generally uniform thickness, is symmetric about an axis 5641 and
defines an hemispherical concave inner articulation surface 5642,
having a beveled edge 5643, and a generally hemispherical outer
bone engagement surface 5644 which preferably has formed thereon at
any suitable location between its apex and its rim a generally
annular outwardly extending protrusion 5646, preferably defining a
generally annular undercut 5648. Alternatively, the protrusion 5646
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 5646 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0549] Preferably, the protrusion 5646 has a cross-sectional
configuration, as can be readily seen in FIG. 47B, which is
characterized in that an underlying surface portion 5650 of
protrusion 5646, at the undercut 5648, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
5652 of protrusion 5646.
[0550] Implantable artificial acetabular socket 5640 is constructed
from an outer layer 5662, an intermediate layer 5664, preferably,
including a plurality of voids 5666, and an inner layer 5668. Outer
layer 5662 is preferably molded of a polyurethane of durometer
number 55 shore D, intermediate layer 5664 is preferably molded of
a polyurethane of durometer number 70 shore D, and inner layer 5668
is preferably molded of a polyurethane of durometer number 80 shore
A. Intermediate layer 5664 preferably includes carbon whiskers.
[0551] In another preferred embodiment of the present invention,
implantable artificial acetabular socket 5640 is constructed from
an outer layer 5662, an intermediate layer 5664, preferably,
including a plurality of voids 5666, and an inner layer 5668. Outer
layer 5662 is preferably molded of a polyurethane of durometer
number 55 shore D, inner layer 5668 is preferably molded of a
polyurethane of durometer number 80 shore A and intermediate layer
5664 is preferably molded of a polyurethane having a fluid
absorption property, such as HydroThane.TM., manufactured by
CardioTech International, Inc., 78E Olympia Ave., Woburn, Mass.,
USA. Inner layer 5668 has formed in articulation surface 5642 a
plurality of thoroughgoing apertures 5670 connecting to voids
5666.
[0552] Reference is now made to FIGS. 48A, 48B, 48C and 48D which
are partially cut away pictorial illustrations of an implantable
artificial acetabular socket constructed and operative in
accordance with still another preferred embodiment of the present
invention and which is particularly suitable for use in a hip
joint.
[0553] As seen in FIGS. 48A, 48B, 48C and 48D, an implantable
artificial acetabular socket, designated by reference numeral 5680,
is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0554] Preferably, implantable artificial acetabular socket 5680 is
of generally uniform thickness, is symmetric about an axis 5681 and
defines an hemispherical concave inner articulation surface 5682,
having a beveled edge 5683, and a generally hemispherical outer
bone engagement surface 5684 which preferably has formed thereon at
any suitable location between its apex and its rim a generally
annular outwardly extending protrusion 5686, preferably defining a
generally annular undercut 5688. Alternatively, the protrusion 5686
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 5686 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0555] Preferably, the protrusion 5686 has a cross-sectional
configuration, which is characterized in that an underlying surface
portion 5690 of protrusion 5686, at the undercut 5688, defines a
slope which is sharper than a corresponding slope of an overlying
surface portion 5692 of protrusion 5686.
[0556] Implantable artificial acetabular socket 5680 is constructed
from an outer layer 5702, as shown in FIG. 48B, and an inner layer
5704, as shown in FIG. 48D, and includes an inserted internal
deformation control element 5706, as shown in FIG. 48C. Outer layer
5702 is preferably molded of a polyurethane of durometer number 55
shore D and inner layer 5704 is preferably molded of a polyurethane
having a durometer number 80 shore A. Internal deformation control
element 5706 is preferably molded of a relatively rigid
polyurethane, typically one having a Shore hardness of
approximately 70 D and may have carbon whiskers embedded therein.
The deformation control element 5706 preferably has an overall
generally annular configuration, defined by a web portion 5712, a
first thickened portion 5714, having a circular cross section, and
a second thickened portion 5716 having a rectangular cross
section.
[0557] Preferably, deformation control element 5706 is configured
and insertably positioned within implantable artificial acetabular
socket 5680 with portions of outer layer 5702 covering it outwardly
and with portions of inner layer 5704 covering it inwardly.
[0558] Reference is now made to FIGS. 49A and 49B, which are
respective pictorial and partially cut away illustrations of an
implantable artificial acetabular socket, constructed and operative
in accordance with still another preferred embodiment of the
present invention, which is particularly suitable for use in a hip
joint.
[0559] As seen in FIGS. 49A and 49B, an implantable artificial
acetabular socket, designated by reference numeral 5750, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0560] Preferably, implantable artificial acetabular socket 5750 is
of generally uniform thickness, is symmetric about an axis 5751 and
defines an hemispherical concave inner articulation surface 5752,
having a beveled edge 5753, and a generally hemispherical outer
bone engagement surface 5754 which preferably has formed thereon at
any suitable location between its apex and its rim a generally
annular outwardly extending protrusion 5756, preferably defining a
generally annular undercut 5758. Alternatively, the protrusion 5756
may be any other suitable non-annular, open or closed, generally
peripheral protrusion. The protrusion 5756 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0561] Preferably, the protrusion 5756 has a cross-sectional
configuration, which is characterized in that an underlying surface
portion 5760 of protrusion 5756, at the undercut 5758, defines a
slope which is sharper than a corresponding slope of an overlying
surface portion 5762 of protrusion 5756.
[0562] It is a particular feature of the artificial implantable
artificial acetabular socket 5750 that it is constructed from a
single layer, preferably, molded of a polyurethane of durometer
number 80 shore A, and includes an inserted internal deformation
control element 5776, illustrated pictorially in FIG. 49B. The
deformation control element 5776 is preferably molded of a
relatively rigid polyurethane, typically one having a Shore
hardness of approximately 70 D, and may have carbon whiskers
embedded therein.
[0563] Preferably, deformation control element 5776 is configured
and insertably positioned within implantable artificial acetabular
socket 5750 with portions of PU material of the single molded layer
covering it outwardly, inwardly and towards the rim of implantable
artificial acetabular socket 5750.
[0564] The deformation control element 5776 preferably has an
overall generally annular configuration defined by a web portion
5782, a first thickened portion 5784, having a circular cross
section, and a second thickened portion 5786, having a circular
cross section. Deformation control element 5776 is further defined
by rectangular cut-outs 5792 separated by flaps 5794 which
terminate in thickened portions 5784 which are also separated by
cut-outs 5792.
[0565] Reference is now made to FIGS. 50A and 50B, which are
respective pictorial and partially cut away illustrations of an
implantable artificial acetabular socket, constructed and operative
in accordance with still another preferred embodiment of the
present invention, which is particularly suitable for use in a hip
joint.
[0566] As seen in FIGS. 50A and 50B, an implantable artificial
acetabular socket, designated by reference numeral 5800, is formed
preferably by injection molding of polyurethane over a reinforcing
deformation control element. Preferred polyurethane materials are
described hereinbelow.
[0567] Preferably, implantable artificial acetabular socket 5800 is
of generally uniform thickness, is symmetric about an axis 5801 and
defines an hemispherical concave inner articulation surface 5802,
having a beveled edge 5803, and a generally hemispherical outer
bone engagement surface 5804 which preferably has formed thereon at
any suitable location between its apex and its rim a generally
annular outwardly extending protrusion 5806, preferably defining a
generally annular undercut 5808. Alternatively, the protrusion 5806
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 5806 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0568] Preferably, the protrusion 5806 has a cross-sectional
configuration, as can be readily seen in FIG. 50A, which is
characterized in that an underlying surface portion 5810 of
protrusion 5806, at the undercut 5808, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
5812 of protrusion 5806.
[0569] Implantable artificial acetabular socket 5800 is constructed
from a single layer, preferably, molded of a polyurethane of
durometer number 80 shore A over internal deformation control
element 5826, illustrated pictorially in FIG. 50B. The deformation
control element 5826 is preferably formed of woven high performance
fibers, such as carbon fibers, KEVLAR.RTM., DYNEEMA.RTM., and glass
fibers, and has an overall generally truncated spherical
configuration defined by arched cut-outs 5836 separated by flaps
5838 which terminate in transverse cylindrical portions 5840 in
which are fixedly disposed rigid rod element 5842 which extends
circumferentially as an open or closed ring.
[0570] It is seen that deformation control element 5826 is
preferably molded entirely within artificial implantable artificial
acetabular socket 5800.
[0571] Reference is now made to FIGS. 51A, 51B and 51C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial femoral head resurfacing
element constructed and operative in accordance with a further
preferred embodiment of the present invention. The implantable
artificial femoral head resurfacing element is intended for
mounting onto a natural femoral head in accordance with a preferred
embodiment of the present invention.
[0572] As seen in FIGS. 51A, 51B and 51C, an implantable artificial
femoral head resurfacing element, designated by reference numeral
5850, is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0573] Preferably, implantable artificial femoral head resurfacing
element 5850 is of generally uneven thickness, with a distinct
thickened portion at its apex. Artificial femoral head resurfacing
element 5850 defines a hemispherical outer articulation surface
5852 and an inner bone engagement surface 5854, having a beveled
edge 5855, which preferably has formed thereon at any suitable
location between its apex and its rim a generally annular inwardly
extending protrusion 5856, preferably defining a generally annular
undercut 5858. Alternatively, the protrusion 5856 may be any other
suitable non-annular, open or closed, generally peripheral,
protrusion. The protrusion 5856 is preferably arranged for snap-fit
engagement with a corresponding groove formed by reaming of a
femoral head.
[0574] Preferably, the protrusion 5856 has a cross-sectional
configuration, as can be readily seen in FIG. 51B, which is
characterized in that an underlying surface portion 5860 of
protrusion 5856, at the undercut 5858, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
5862 of protrusion 5856.
[0575] Implantable artificial femoral head resurfacing element 5850
defines an uneven thickness portion 5876 extending between
thickened apex portion and the protrusion 5856. The thickness of
uneven thickness portion 5876 varies at various regions,
corresponding to various portions of the bone engagement surface
5854, which renders it an asymmetric configuration requiring a
definition of the implanting orientation with regard to the femoral
head. Preferably, a marking numeral 5870, such as the writing
trochanter, designating and corresponding to the great trochanter,
is used to position implantable artificial femoral head resurfacing
element 5850 in its designed orientation by placing the marking
5870 facing the great trochanter.
[0576] As can be seen in FIG. 51B, preferably, uneven thickness
portion 5876 comprises a region 5878 of a thickness less than the
average thickness of uneven thickness portion 5876, located facing
marking 5870, and a region 5880 of a thickness greater than the
average thickness of uneven thickness portion 5876, located away
from marking 5870.
[0577] As can be seen in FIG. 51C, preferably, uneven thickness
portion 5876 may include other variations of thickness across
uneven thickness portion 5876.
[0578] Reference is now made to FIGS. 52A, 52B and 52C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial femoral head resurfacing
element constructed and operative in accordance with another
preferred embodiment of the present invention.
[0579] As seen in FIGS. 52A, 52B, and 52C, an implantable
artificial femoral head resurfacing element, designated by
reference numeral 5900, is formed preferably by injection molding
of multi layers of polyurethane including a fluid absorbing layer.
Preferred polyurethane materials are described hereinbelow.
[0580] Preferably, implantable artificial femoral head resurfacing
element 5900 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about in axis 5901 and
defines an hemispherical outer articulation surface 5902 and a
generally hemispherical inner bone engagement surface 5904, having
a beveled edge 5905, which preferably has formed thereon at any
suitable location between its apex and its rim a generally annular
inwardly extending protrusion 5906, preferably defining a generally
annular undercut 5908. Alternatively, the protrusion 5906 may be
any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 5906 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a femoral head.
[0581] Preferably, the protrusion 5906 has a cross-sectional
configuration, as can be readily seen in FIG. 52B, which is
characterized in that an underlying surface portion 5910 of
protrusion 5906, at the undercut 5908, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
5912 of protrusion 5906.
[0582] Implantable artificial femoral head resurfacing element 5900
is constructed from an inner layer 5922, an intermediate layer
5924, which preferably includes a plurality of voids 5926, and an
outer layer 5928. Inner layer 5922 is, preferably, molded of a
polyurethane of durometer number 55 shore D, outer layer 5928 is,
preferably, molded of a polyurethane of durometer number 80 shore A
and intermediate layer 5924 is, preferably, molded of a
polyurethane having a fluid absorption property, such as
HydroThane.TM., manufactured by CardioTech International, Inc., 78E
Olympia Ave., Woburn, Mass., USA. Outer layer 5928 has formed in
articulation surface 5902 a plurality of thoroughgoing apertures
5929 connecting to voids 5926.
[0583] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
femoral head resurfacing element 5900 at the apex thereof, any
suitable portion thereof may be of non-uniform thickness.
[0584] Reference is now made to FIGS. 53A, 53B and 53C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial femoral head resurfacing
element, intended for mounting onto a natural femoral head, in
accordance with still another preferred embodiment of the present
invention.
[0585] As seen in FIGS. 53A, 53B, and 53C, an implantable
artificial femoral head resurfacing element, designated by
reference numeral 5950, is formed preferably by injection molding
of polyurethane formed over a deformation control element.
Preferred polyurethane materials are described hereinbelow.
[0586] Preferably, implantable artificial femoral head resurfacing
element 5950 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about an axis 5951 and
defines an hemispherical outer articulation surface 5952 and a
generally hemispherical inner bone engagement surface 5954, having
a beveled edge 5955, which preferably has formed thereon at any
suitable location between its apex and its rim a generally annular
inwardly extending protrusion 5956, preferably defining a generally
annular undercut 5958. Alternatively, the protrusion 5956 may be
any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 5956 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a femoral head.
[0587] Preferably, the protrusion 5956 has a cross-sectional
configuration, as can be readily seen in FIG. 53B, which is
characterized in that an underlying surface portion 5960 of
protrusion 5956, at the undercut 5958, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
5962 of protrusion 5956.
[0588] Implantable artificial femoral head resurfacing element 5950
is constructed from a single layer molded of a polyurethane of
durometer number 80 shore A, and includes an inserted array 5964 of
internal deformation control elements 5966, as seen in FIG. 53C.
The deformation control elements 5966 are preferably molded of a
relatively rigid polyurethane, typically one having a Shore
hardness of approximately 70 D and may have carbon whiskers
embedded therein.
[0589] The deformation control elements 5966, preferably, have an
overall generally partial annular configuration including a web
portion 5968, a first thickened portion 5970, having a circular
cross section, and a second thickened portion 5972 having a
rectangular cross section. Preferably, deformation control elements
5966 are configured and insertably positioned within implantable
artificial femoral head resurfacing element 5950 with portions of
PU material of the single molded layer covering them outwardly,
inwardly and towards the rim of implantable artificial femoral head
resurfacing element 5950.
[0590] Reference is now made to FIGS. 54A, 54B and 54C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial femoral head resurfacing
element, intended for mounting onto a natural femoral head, in
accordance with yet another preferred embodiment of the present
invention.
[0591] As seen in FIGS. 54A, 54B, and 54C, an implantable
artificial femoral head resurfacing element, designated by
reference numeral 6000, is formed preferably by injection molding
of multi layers of polyurethane formed over a deformation control
element. Preferred polyurethane materials are described
hereinbelow.
[0592] Preferably, implantable artificial femoral head resurfacing
element 6000 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about an axis 6001 and
defines an hemispherical outer articulation surface 6002 and a
generally hemispherical inner bone engagement surface 6004, having
a beveled edge 6005, which preferably has formed thereon at any
suitable location between its apex and its rim a generally annular
inwardly extending protrusion 6006, preferably defining a generally
annular undercut 6008. Alternatively, the protrusion 6006 may be
any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 6006 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a femoral head.
[0593] Preferably, the protrusion 6006 has a cross-sectional
configuration, as can be readily seen in FIG. 54B, which is
characterized in that an underlying surface portion 6010 of
protrusion 6006, at the undercut 6008, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
6012 of protrusion 6006.
[0594] Implantable artificial femoral head resurfacing element 6000
is constructed from an outer layer 6022 and an inner layer 6024 and
includes an inserted array 6026 of internal deformation control
elements 6028, as seen in FIG. 54C. Outer layer 6022 is,
preferably, molded of a polyurethane of durometer number 80 shore
A, and inner layer 6024 is, preferably, molded of a polyurethane
having a durometer number 55 shore D. The deformation control
elements 6028 are preferably molded of a relatively rigid
polyurethane, typically one having a Shore hardness of
approximately 70 D and may have carbon whiskers embedded
therein.
[0595] The deformation control elements 6028 preferably have an
overall generally partial annular configuration including a web
portion 6032, a first thickened portion 6034, having a circular
cross section, and a second thickened portion 6036, having a
rectangular cross section. Preferably, deformation control elements
6028 are configured and insertably positioned within implantable
artificial femoral head resurfacing element 6000 with portions of
outer layer 6022 covering them outwardly and with portions of inner
layer 6024 covering them inwardly and towards the rim of
implantable artificial femoral head resurfacing element 6000.
[0596] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
femoral head resurfacing element 6000 at the apex thereof, any
suitable portion thereof may be of non-uniform thickness.
[0597] Reference is now made to FIGS. 55A, 55B and 55C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial femoral head resurfacing
element constructed and operative in accordance with a further
preferred embodiment of the present invention. The implantable
artificial femoral head resurfacing element is intended for
mounting onto a natural femoral head in accordance with a preferred
embodiment of the present invention.
[0598] As seen in FIGS. 55A, 55B and 55C, an implantable artificial
femoral head resurfacing element, designated by reference numeral
6100, is formed preferably by injection molding of polyurethane
over a reinforcing deformation control element. Preferred
polyurethane materials are described hereinbelow.
[0599] Preferably, implantable artificial femoral head resurfacing
element 6100 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about an axis 6101 and
defines an hemispherical outer articulation surface 6102 and a
generally hemispherical inner bone engagement surface 6104, having
a beveled edge 6105, which preferably has formed thereon, at any
suitable location between its apex and its rim, a generally annular
inwardly extending protrusion 6106, preferably defining a generally
annular undercut 6108. Alternatively, the protrusion 6106 may be
any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 6106 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a femoral head.
[0600] Preferably, the protrusion 6106 has a cross-sectional
configuration, as can be readily seen in FIG. 55B, which is
characterized in that an underlying surface portion 6110 of
protrusion 6106, at the undercut 6108, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
6112 of protrusion 6106.
[0601] It is a particular feature of the artificial femoral head
resurfacing element 6100 that it includes an internal reinforcing
deformation control element, which is designated by reference
numeral 6114 and illustrated pictorially in FIG. 55C. The
deformation control element 6114 is preferably formed of woven high
performance fibers, such as carbon fibers, KEVLAR.RTM.,
DYNEEMA.RTM., and glass fibers, and has an overall generally
truncated spherical configuration defined by arched cut-outs 6116
separated by flaps 6118 which terminate in transverse cylindrical
portions 6120 in which are fixedly disposed rigid rod elements
6122, ends 6124 of which extend beyond flaps 6118, as shown.
[0602] It is seen that insert 6114 is preferably molded entirely
within artificial femoral head resurfacing element 6100.
[0603] Reference is now made to FIGS. 56A, 56B and 56C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a further preferred
embodiment of the present invention and which is particularly
suitable for use in a hip joint.
[0604] As seen in FIGS. 56A, 56B and 56C, an implantable artificial
acetabular socket, designated by reference numeral 6200, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0605] Preferably, implantable artificial acetabular socket 6200
comprises a surface of rotation which is symmetric about an axis
6201 and defines a generally hemispherical outer bone engagement
surface 6204 which preferably has formed thereon, at any suitable
location between its apex and its rim, a generally annular
outwardly extending protrusion 6206, preferably defining a
generally annular undercut 6208. Alternatively, the protrusion 6206
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 6206 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0606] Preferably, the protrusion 6206 has a cross-sectional
configuration, as can be readily seen in FIG. 56B, which is
characterized in that an underlying surface portion 6210 of
protrusion 6206, at the undercut 6208, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
6212 of protrusion 6206.
[0607] It is a particular feature of the implantable artificial
acetabular socket 6200 that an inner surface thereof defines two
portions of spherical surfaces of rotation having different radii.
A first portion, designated by reference numeral 6214, having a
radius designated by reference numeral 6216, extends from a beveled
edge 6218 to a peripheral step 6220. A second portion, designated
by reference numeral 6224, and having a radius designated by
reference numeral 6226, which radius is larger than radius 6216,
extends from step 6220 to the apex, here designated by reference
numeral 6228.
[0608] It is appreciated that surface 6224 need not be spherical,
provided that it does not extend to a location within the spherical
volume partially defined by surface portion 6214 and thus defines a
recess extending beyond that spherical volume.
[0609] Reference is now made to FIGS. 57A, 57B and 57C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a further preferred
embodiment of the present invention and which is particularly
suitable for use in a hip joint.
[0610] As seen in FIGS. 57A, 57B and 57C, an implantable artificial
acetabular socket, designated by reference numeral 6350, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0611] Preferably, implantable artificial acetabular socket 6350
comprises a surface of rotation which is symmetric about an axis
6351 and defines a generally hemispherical outer bone engagement
surface 6354 which preferably has formed thereon, at any suitable
location between its apex and its rim, a generally annular
outwardly extending protrusion 6356, preferably defining a
generally annular undercut 6358. Alternatively, the protrusion 6356
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 6356 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0612] Preferably, the protrusion 6356 has a cross-sectional
configuration, as can be readily seen in FIG. 57B, which is
characterized in that an underlying surface portion 6360 of
protrusion 6356, at the undercut 6358, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
6362 of protrusion 6356.
[0613] Artificial acetabular socket 6350 is similar to artificial
acetabular socket 1100 shown is FIGS. 1A-1C, except that an inner
articulation surface 6364 defines an additional hemispherical
concave layer 6366 along a portion thereof. Additional concave
layer 6366 is defined by a peripheral step 6370 and extends from
peripheral step 6370 to the apex 6372 of acetabular socket 6350.
Additional concave layer 6366 also continues below peripheral step
6370, underlying a portion of inner surface 6364 and continuing
until a lower edge 6374, and defines a recess provided to allow for
the accumulation of synovial fluid for lubrication of the
articulation surface 6364.
[0614] It is appreciated that the provision of layer 6366 further
defines inner articulation surface 6364 as having a horseshoe
shaped portion to more closely approximate the acetabular articular
surface of the natural acetabulum. This provides for an
articulation surface that more closely approximates the natural
articulation surface.
[0615] Reference is now made to FIGS. 58A and 58B, which are
respective partially cut away pictorial and sectional illustrations
of an implantable artificial acetabular socket constructed and
operative in accordance with a further preferred embodiment of the
present invention and which is particularly suitable for use in a
hip joint.
[0616] As seen in FIGS. 58A and 58B, an implantable artificial
acetabular socket, designated by reference numeral 7100, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0617] Preferably, implantable artificial acetabular socket 7100 is
of generally uniform thickness, is symmetric about an axis 7101 and
defines an hemispherical concave inner articulation surface 7102,
having a beveled edge 7103, and a generally hemispherical outer
bone engagement surface 7104, which preferably has formed thereon,
at any suitable location between its apex and its rim, a generally
annular outwardly extending protrusion 7106, preferably defining a
generally annular undercut 7108. Alternatively, the protrusion 7106
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 7106 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0618] Preferably, the protrusion 7106 has a cross-sectional
configuration, as can be readily seen in FIG. 58B, which is
characterized in that an underlying surface portion 7110 of
protrusion 7106, at the undercut 7108, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
7112 of protrusion 7106.
[0619] Artificial acetabular socket 7100 is similar to artificial
acetabular socket 1100 shown is FIGS. 1A-1C, except that inner
articulation surface 7102 is further defined by a hexagonal
configuration pattern, which includes hexagonal recessed surface
portions 7120. Recessed surface portions 7120 may be connected or
isolated from each other and are provided to allow for the
accumulation of synovial fluid for lubrication of the articulation
surface 7102. Additionally, the hexagonal recessed configuration
provides for reduced surface contact area, which reduces friction.
It is appreciated that, even though the illustrated embodiment
shows a hexagonal configuration, any suitable configuration of
recessed surface portions may be provided.
[0620] Reference is now made to FIGS. 59A and 59B, which are
respective partially cut away pictorial and sectional illustrations
of an implantable artificial acetabular socket constructed and
operative in accordance with a further preferred embodiment of the
present invention and which is particularly suitable for use in a
hip joint.
[0621] As seen in FIGS. 59A and 59B, an implantable artificial
acetabular socket, designated by reference numeral 7150, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0622] Preferably, implantable artificial acetabular socket 7150 is
of generally uniform thickness, is symmetric about an axis 7151 and
defines an hemispherical concave inner articulation surface 7152,
having a beveled edge 7153, and a generally hemispherical outer
bone engagement surface 7154, which preferably has formed thereon,
at any suitable location between its apex and its rim, a generally
annular outwardly extending protrusion 7156, preferably defining a
generally annular undercut 7158. Alternatively, the protrusion 7156
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 7156 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0623] Preferably, the protrusion 7156 has a cross-sectional
configuration, as can be readily seen in FIG. 59B, which is
characterized in that an underlying surface portion 7160 of
protrusion 7156, at the undercut 7158, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
7162 of protrusion 7156.
[0624] Artificial acetabular socket 7150 is similar to artificial
acetabular socket 7100 shown is FIGS. 58A-58B, except that inner
surface 7152 is further defined by a hexagonal configuration
pattern, which includes hexagonal recessed surface portions 7170
connected by peripheral channels 7174. Peripheral channels 7174 are
preferably interconnected and continuous and are provided to allow
synovial fluid to pass through for lubrication of the articulation
surface 7152. Additionally, the hexagonal recessed configuration
provides for reduced surface contact area, which reduces friction.
It is appreciated that, even though the illustrated embodiment
shows a hexagonal configuration, any suitable configuration of
recessed surface portions may be provided.
[0625] Reference is now made to FIGS. 60A, 60B and 60C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a further preferred
embodiment of the present invention and which is particularly
suitable for use in a hip joint.
[0626] As seen in FIGS. 60A, 60B and 60C, an implantable artificial
acetabular socket, designated by reference numeral 7200, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0627] Preferably, implantable artificial acetabular socket 7200 is
of generally uniform thickness, is symmetric about an axis 7201 and
defines an hemispherical concave inner articulation surface 7202,
having a beveled edge 7203, and a generally hemispherical outer
bone engagement surface 7204 which preferably has formed thereon,
at any suitable location between its apex and its rim, a generally
annular outwardly extending protrusion 7206, preferably defining a
generally annular undercut 7208. Alternatively, the protrusion 7206
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 7206 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0628] Preferably, the protrusion 7206 has a cross-sectional
configuration, as can be readily seen in FIG. 60B, which is
characterized in that an underlying surface portion 7210 of
protrusion 7206, at the undercut 7208, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
7212 of protrusion 7206.
[0629] It is a particular feature of the implantable artificial
acetabular socket 7200 that it includes an internal reinforcing
deformation control element, which is designated by reference
numeral 7214 and illustrated pictorially in FIG. 60C. The
deformation control element 7214 is preferably molded of a
relatively rigid polyurethane, typically one having a Shore
hardness of approximately 70 D and may have carbon whiskers
embedded therein. The deformation control element 7214 preferably
has an overall generally truncated spherical configuration defined
by rectangular cut-outs 7216 separated by flaps 7218 which
terminate in thickened portions 7220. It is seen that deformation
control element 7214 is preferably molded entirely within
artificial acetabular socket 7200.
[0630] Reference is now made to FIGS. 61A, 61B and 61C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial femoral head resurfacing
element constructed and operative in accordance with a further
preferred embodiment of the present invention. The implantable
artificial femoral head resurfacing element is intended for
mounting onto a natural femoral head in accordance with a preferred
embodiment of the present invention.
[0631] As seen in FIGS. 61A, 61B and 61C, an implantable artificial
femoral head resurfacing element, designated by reference numeral
7250, is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0632] Preferably, implantable artificial femoral head resurfacing
element 7250 is of generally uneven thickness, with a distinct
thickened portion at its apex. Artificial femoral head resurfacing
element 7250 defines a hemispherical outer articulation surface
7252 and an inner bone engagement surface 7254, having a beveled
edge 7255, which preferably has formed thereon at any suitable
location between its apex and its rim a generally annular inwardly
extending protrusion 7256, preferably defining a generally annular
undercut 7258. Alternatively, the protrusion 7256 may be any other
suitable non-annular, open or closed, generally peripheral,
protrusion. The protrusion 7256 is preferably arranged for snap-fit
engagement with a corresponding groove formed by reaming of a
femoral head.
[0633] Preferably, the protrusion 7256 has a cross-sectional
configuration, as can be readily seen in FIG. 61B, which is
characterized in that an underlying surface portion 7260 of
protrusion 7256, at the undercut 7258, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
7262 of protrusion 7256.
[0634] It is a particular feature of the implantable artificial
femoral head resurfacing element 7250 that outer articulation
surface 7252 further defines two portions of spherical surfaces of
rotation. A first portion, designated by reference numeral 7264,
extends from beveled edge 7255 to a generally circular rim 7270. A
second portion, designated by reference numeral 7274, extends from
rim 7270 to the apex, here designated by reference numeral 7278. As
seen in FIG. 61A, rim 7270 is not at a uniform distance from
beveled edge 7255. The provision of rim 7270 allows artificial
femoral head resurfacing element 7250 to more closely approximate a
natural femoral head, which reduces friction and provides a thicker
portion aligned with the area of greatest stress applied to the
surface element during articulation. It is appreciated that, even
though, in the illustrated embodiment of FIGS. 61A-61C, rim 7270 is
circular, any suitable configuration of rim 7270, may be provided.
One such alternate configuration of rim 7270 is shown hereinbelow
in FIGS. 62A-62C.
[0635] As shown in FIGS. 61A-61C, artificial femoral head
resurfacing element 7250 need not have a uniform outer articulation
surface, but is thickened asymmetrically to provide a thicker
portion where required by the specific joint reaction force of the
joint with which it is articulating.
[0636] Reference is now made to FIGS. 62A, 62B and 62C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial femoral head resurfacing
element constructed and operative in accordance with a further
preferred embodiment of the present invention. The implantable
artificial femoral head resurfacing element is intended for
mounting onto a natural femoral head in accordance with a preferred
embodiment of the present invention.
[0637] As seen in FIGS. 62A, 62B and 62C, an implantable artificial
femoral head resurfacing element, designated by reference numeral
7300, is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0638] Preferably, implantable artificial femoral head resurfacing
element 7300 is of generally uneven thickness, with a distinct
thickened portion at its apex. Artificial femoral head resurfacing
element 7300 defines a hemispherical outer articulation surface
7302 and an inner bone engagement surface 7304, having a beveled
edge 7305, which preferably has formed thereon at any suitable
location between its apex and its rim a generally annular inwardly
extending protrusion 7306, preferably defining a generally annular
undercut 7308. Alternatively, the protrusion 7306 may be any other
suitable non-annular, open or closed, generally peripheral,
protrusion. The protrusion 7306 is preferably arranged for snap-fit
engagement with a corresponding groove formed by reaming of a
femoral head.
[0639] Preferably, the protrusion 7306 has a cross-sectional
configuration, as can be readily seen in FIG. 62B, which is
characterized in that an underlying surface portion 7310 of
protrusion 7306, at the undercut 7308, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
7312 of protrusion 7306.
[0640] It is a particular feature of the implantable artificial
femoral head resurfacing element 7300 that outer articulation
surface 7302 further defines two portions of spherical surfaces of
rotation. A first portion, designated by reference numeral 7314,
extends from beveled edge 7305 to a rim 7320. A second portion,
designated by reference numeral 7324, extends from rim 7320 to the
apex, here designated by reference numeral 7328. As seen in FIG.
62A, rim 7320 is not at a uniform distance from beveled edge 7305.
The provision of rim 7320 allows artificial femoral head
resurfacing element 7300 to more closely approximate a natural
femoral head, which reduces friction and provides a thicker portion
aligned with the area of greatest stress applied to the surface
element during articulation.
[0641] As shown in FIGS. 62A-62C, artificial femoral head
resurfacing element 7300 need not have a uniform outer articulation
surface, but is thickened asymmetrically to provide a thicker
portion where required by the specific joint reaction force of the
joint with which it is articulating.
[0642] Reference is now made to FIGS. 63A and 63B, which are
respective pictorial and sectional illustrations of an implantable
artificial femoral or humeral head resurfacing element constructed
and operative in accordance with still another preferred embodiment
of the present invention. The implantable artificial femoral or
humeral head resurfacing element is intended for mounting onto a
natural femoral or humeral head in accordance with a preferred
embodiment of the present invention.
[0643] As seen in FIGS. 63A and 63B, an implantable artificial
femoral or humeral head resurfacing element, designated by
reference numeral 7400, is formed preferably by injection molding
of polyurethane. Preferred polyurethane materials are described
hereinbelow.
[0644] Preferably, implantable artificial femoral or humeral head
resurfacing element 7400 is of generally uniform thickness, other
than at its apex which is thickened, is symmetric about an axis
7401 and defines an hemispherical outer articulation surface 7402
and a generally hemispherical inner bone engagement surface 7404,
having a beveled edge 7405, which preferably has formed thereon, at
any suitable location between its apex and its rim, a generally
annular inwardly extending protrusion 7406, preferably defining a
generally annular undercut 7408. Alternatively, the protrusion 7406
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 7406 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a femoral or humeral head
[0645] Preferably, the protrusion 7406 has a cross-sectional
configuration, as can be readily seen in FIG. 63B, which is
characterized in that an underlying surface portion 7410 of
protrusion 7406, at the undercut 7408, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
7412 of protrusion 7406.
[0646] The outer articulation surface 7402 of implantable
artificial femoral or humeral head resurfacing element 7400
preferably comprises a hexagonal configuration pattern, which
includes hexagonal articulating surface portions 7420 defined by
peripheral channels 7424. Peripheral channels 7424 are preferably
interconnected and continuous and are provided to allow synovial
fluid to pass through for lubrication of the articulation surface
7402. Additionally, the hexagonal recessed configuration provides
for reduced surface contact area, which reduces friction. It is
appreciated that, even though the illustrated embodiment shows a
hexagonal configuration, any suitable configuration of channels and
surface portions may be provided.
[0647] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
femoral head resurfacing element 7400 at the apex thereof, any
suitable portion thereof may be of non-uniform thickness.
[0648] Reference is now made to FIGS. 64A and 64B, which are
respective pictorial and sectional illustrations of an implantable
artificial femoral or humeral head resurfacing element constructed
and operative in accordance with still another preferred embodiment
of the present invention. The implantable artificial femoral or
humeral head resurfacing element is intended for mounting onto a
natural femoral or humeral head in accordance with a preferred
embodiment of the present invention.
[0649] As seen in FIGS. 64A and 64B, an implantable artificial
femoral or humeral head resurfacing element, designated by
reference numeral 7500, is formed preferably by injection molding
of polyurethane. Preferred polyurethane materials are described
hereinbelow.
[0650] Preferably, implantable artificial femoral or humeral head
resurfacing element 7500 is of generally uniform thickness, other
than at its apex which is thickened, is symmetric about an axis
7501 and defines an hemispherical outer articulation surface 7502
and a generally hemispherical inner bone engagement surface 7504,
having a beveled edge 7505, which preferably has formed thereon, at
any suitable location between its apex and its rim, a generally
annular inwardly extending protrusion 7506, preferably defining a
generally annular undercut 7508. Alternatively, the protrusion 7506
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 7506 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a femoral or humeral head.
[0651] Preferably, the protrusion 7506 has a cross-sectional
configuration, as can be readily seen in FIG. 64B, which is
characterized in that an underlying surface portion 7510 of
protrusion 7506, at the undercut 7508, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
7512 of protrusion 7506.
[0652] The outer articulation surface 7502 of implantable
artificial femoral or humeral head resurfacing element 7500
preferably comprises a hexagonal configuration pattern, which
includes hexagonal recessed surface portions 7520 defined by
peripheral articulating surface elements 7524. Recessed surface
portions 7520 may be connected or isolated from each other and are
provided to allow for the accumulation of synovial fluid for
lubrication of the articulation surface 7502. Additionally, the
hexagonal recessed configuration provides for reduced surface
contact area, which reduces friction. It is appreciated that, even
though the illustrated embodiment shows a hexagonal configuration,
any suitable configuration of articulating surface elements and
recessed surface portions may be provided.
[0653] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
femoral head resurfacing element 7500 at the apex thereof, any
suitable portion thereof may be of non-uniform thickness.
[0654] Reference is now made to FIGS. 65A, 65B and 65C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial femoral head resurfacing
element constructed and operative in accordance with a further
preferred embodiment of the present invention. The implantable
artificial femoral head resurfacing element is intended for
mounting onto a natural femoral head in accordance with a preferred
embodiment of the present invention.
[0655] As seen in FIGS. 65A, 65B and 65C, an implantable artificial
femoral head resurfacing element, designated by reference numeral
7550, is formed preferably by injection molding of polyurethane
over a reinforcing deformation control element. Preferred
polyurethane materials are described hereinbelow.
[0656] Preferably, implantable artificial femoral head resurfacing
element 7550 is of generally uniform thickness, other than at its
apex which is thickened, is symmetric about an axis 7551 and
defines an hemispherical outer articulation surface 7552 and a
generally hemispherical inner bone engagement surface 7554, having
a beveled edge 7555, which preferably has formed thereon, at any
suitable location between its apex and its rim, a generally annular
inwardly extending protrusion 7556, preferably defining a generally
annular undercut 7558. Alternatively, the protrusion 7556 may be
any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 7556 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a femoral head.
[0657] Preferably, the protrusion 7556 has a cross-sectional
configuration, as can be readily seen in FIG. 65B, which is
characterized in that an underlying surface portion 7560 of
protrusion 7556, at the undercut 7558, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
7562 of protrusion 7556.
[0658] It is a particular feature of the artificial femoral head
resurfacing element 7550 that it includes an internal reinforcing
deformation control element, which is designated by reference
numeral 7564 and illustrated pictorially in FIG. 65C. The
deformation control element 7564 is preferably formed of woven high
performance fibers, such as carbon fibers, KEVLAR.RTM.,
DYNEEMA.RTM., and glass fibers, and has an overall generally
truncated spherical configuration defined by arched cut-outs 7566
separated by flaps 7568 which terminate in thickened portions 7570.
It is seen that insert 7564 is preferably molded entirely within
artificial femoral head resurfacing element 7550.
[0659] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
femoral head resurfacing element 7550 at the apex thereof, any
suitable portion thereof may be of non-uniform thickness.
[0660] Reference is now made to FIGS. 66A, 66B, and 66C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a further preferred
embodiment of the present invention and which is particularly
suitable for use in a hip joint.
[0661] As seen in FIGS. 66A, 66B, and 66C, an implantable
artificial acetabular socket, designated by reference numeral 7600,
is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0662] Preferably, implantable artificial acetabular socket 7600
defines an inner surface 7602 which is symmetric about an axis
7601. Acetabular socket 7600 also preferably has a beveled edge
7603 and defines a generally hemispherical outer bone engagement
surface 7604 which preferably has formed thereon, at any suitable
location between its apex and its rim, a generally annular
outwardly extending protrusion 7606, preferably defining a
generally annular undercut 7608. Alternatively, the protrusion 7606
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 7606 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0663] Preferably, the protrusion 7606 has a cross-sectional
configuration, as can be readily seen in FIG. 66B, which is
characterized in that an underlying surface portion 7610 of
protrusion 7606, at the undercut 7608, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
7612 of protrusion 7606.
[0664] It is a particular feature of the implantable artificial
acetabular socket 7600 that a portion of outer bone engagement
surface 7604 thereof defines a thickened portion 7614, preferably
extending from a location generally atop inner apex 7616 of
acetabular socket 7600 to the protrusion 7606. Thickened portion
7614 is preferably aligned with the natural acetabular recess, and
is provided to allow a proper fit with a reamed acetabulum, without
requiring reaming of the entire surface of the acetabulum down to
the level of the acetabular recess, as described hereinbelow with
reference to FIG. 69A. The thickened portion 7614 preferably allows
for a less invasive procedure and also provides a thicker shock
absorbing surface. It is appreciated that, even though the
illustrated embodiment shows a circular configuration, any suitable
configuration of thickened portion 7614 may be provided.
[0665] It is appreciated that thickened portion 7614 of acetabular
socket 7600 may alternatively be oriented, as described hereinbelow
with reference to FIG. 69B, so as to align thickened portion 7614
with the area of greatest applied force.
[0666] Reference is now made to FIGS. 67A, 67B, and 67C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a further preferred
embodiment of the present invention and which is particularly
suitable for use in a hip joint.
[0667] As seen in FIGS. 67A, 67B, and 67C, an implantable
artificial acetabular socket, designated by reference numeral 7700,
is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0668] Preferably, implantable artificial acetabular socket 7700
defines an inner surface 7702 which is symmetric about an axis
7701. Acetabular socket 7700 also preferably has a beveled edge
7703 and defines a generally hemispherical outer bone engagement
surface 7704 which preferably has formed thereon, at any suitable
location between its apex and its rim, a generally annular
outwardly extending protrusion 7706, preferably defining a
generally annular undercut 7708. Alternatively, the protrusion 7706
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 7706 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0669] Preferably, the protrusion 7706 has a cross-sectional
configuration, as can be readily seen in FIG. 67B, which is
characterized in that an underlying surface portion 7710 of
protrusion 7706, at the undercut 7708, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
7712 of protrusion 7706.
[0670] It is a particular feature of the implantable artificial
acetabular socket 7700 that a portion of outer bone engagement
surface 7704 thereof defines multiple thickened portions 7714 and
7715, preferably extending from a location generally atop inner
apex 7716 of acetabular socket 7700 to the protrusion 7706.
Thickened portion 7714 is preferably aligned with the natural
acetabular recess, and is provided to allow a proper fit with a
reamed acetabulum, without requiring reaming of the entire surface
of the acetabulum down to the level of the acetabular recess, as
described hereinbelow with reference to FIG. 69C. The thickened
portion 7714 preferably allows for a less invasive procedure and
also provides a thicker shock absorbing surface. It is appreciated
that, even though the illustrated embodiment shows a circular
configuration, any suitable configuration of thickened portion 7714
may be provided. Thickened portion 7715 or acetabular socket 7600
is oriented, as described hereinbelow with reference to FIG. 69C,
so as to be aligned with the area of greatest applied force.
[0671] Reference is now made to FIGS. 68A, 68B, and 68C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a further preferred
embodiment of the present invention and which is particularly
suitable for use in a hip joint
[0672] As seen in FIGS. 68A, 68B, and 68C, an implantable
artificial acetabular socket, designated by reference numeral 7900,
is formed preferably by injection molding of polyurethane.
Preferred polyurethane materials are described hereinbelow.
[0673] Preferably, implantable artificial acetabular socket 7900
defines an inner surface 7902 which is symmetric about an axis
7901. Acetabular socket 7900 also preferably has a beveled edge
7903 and defines a generally hemispherical outer bone engagement
surface 7904 which preferably has formed thereon, at any suitable
location between its apex and its rim, a generally annular
outwardly extending protrusion 7906, preferably defining a
generally annular undercut 7908. Alternatively, the protrusion 7906
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 7906 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0674] Preferably, the protrusion 7906 has a cross-sectional
configuration, as can be readily seen in FIG. 68B, which is
characterized in that an underlying surface portion 7910 of
protrusion 7906, at the undercut 7908, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
7912 of protrusion 7906.
[0675] It is a particular feature of the implantable artificial
acetabular socket 7900 that a portion of outer bone engagement
surface 7904 thereof defines a thickened portion 7914, preferably
extending from a location generally atop inner apex 7916 of
acetabular socket 7900 to the protrusion 7906. Thickened portion
7914 is preferably aligned with the peak direction of the joint
reaction force of the joint with which it is articulating.
Thickened portion 7914 also preferably includes hollow portion
7918, which provides for attenuation of the stresses incurred at
the joint. It is appreciated that, even though the illustrated
embodiment shows a generally circular configuration, any suitable
configuration of thickened portion 7914 and hollow portion 7918 may
be provided.
[0676] Reference is now made to FIGS. 69A, 69B, 69C and 69D, which
are sectional illustrations of a hip joint employing the
implantable artificial acetabular sockets of FIGS. 66A-68C
implanted in a reamed acetabulum.
[0677] As seen in FIG. 69A, implantable artificial acetabular
socket 7600 of FIGS. 66A-66C is shown implanted in acetabulum 7950
in a first orientation, where thickened portion 7614 is aligned
with the natural acetabular recess 7952. Provision of thickened
portion 7614 allows acetabular socket 7600 to fit into acetabulum
7950 without requiring reaming of a hemispherical portion thereof,
as indicated by dotted lines 7954. This allows for a less invasive
procedure and also provides a thicker shock absorbing surface.
[0678] FIG. 69B illustrates implantable artificial acetabular
socket 7600 of FIGS. 66A-66C implanted in acetabulum 7960 in a
second orientation, where thickened portion 7614 is oriented so as
to align thickened portion 7614 with the area of greatest applied
force.
[0679] FIG. 69C illustrates implantable artificial acetabular
socket 7700 of FIGS. 67A-67C implanted in acetabulum 7970.
Thickened portion 7714 is aligned with the natural acetabular
recess 7972. Provision of thickened portion 7714 allows acetabular
socket 7700 to fit into acetabulum 7970 without requiring reaming
of a hemispherical portion thereof, as indicated by dotted lines
7974. This allows for a less invasive procedure and also provides a
thicker shock absorbing surface. This embodiment requires
additional reaming over that shown in FIG. 69A, to allow for the
placement of thickened portion 7715 in the area of greatest applied
force.
[0680] FIG. 69D shows implantable artificial acetabular socket 7900
of FIGS. 68A-68C implanted in acetabulum 7980, where thickened
portion 7914 is oriented so as to align thickened portion 7914 with
the area of greatest applied force. As seen in FIG. 69D, hollow
portion 7918 is provided for attenuation of the stresses incurred
at the joint.
[0681] Reference is now made to FIGS. 70A, 70B, and 70C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a further preferred
embodiment of the present invention.
[0682] Preferably, implantable artificial acetabular socket 8000 is
of generally uniform thickness, is symmetric about an axis 8001 and
defines an hemispherical concave inner articulation surface 8002,
having a beveled edge 8003, and a generally hemispherical outer
bone engagement surface 8004, which preferably has formed thereon,
at any suitable location between its apex and its rim, a generally
annular outwardly extending protrusion 8006, preferably defining a
generally annular undercut 8008. Alternatively, the protrusion 8006
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 8006 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0683] Preferably, the protrusion 8006 has a cross-sectional
configuration, as can be readily seen in FIG. 70B, which is
characterized in that an underlying surface portion 8010 of
protrusion 8006, at the undercut 8008, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
8012 of protrusion 8006.
[0684] It is a particular feature of the implantable artificial
acetabular socket 8000 that an edge portion 8020 thereof is formed
with an inward groove 8022. Inward groove 8022 is provided to allow
for the growth of bone or fibrous tissue following the implantation
of acetabular socket 8000 and to promote biological fixation of
acetabular socket 8000.
[0685] Reference is now made to FIGS. 71A, 71B, and 71C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a further preferred
embodiment of the present invention.
[0686] Preferably, implantable artificial acetabular socket 8100 is
of generally uniform thickness, is symmetric about an axis 8101 and
defines an hemispherical concave inner articulation surface 8102,
having a beveled edge 8103, and a generally hemispherical outer
bone engagement surface 8104, which preferably has formed thereon,
at any suitable location between its apex and its rim, a generally
annular outwardly extending protrusion 8106, preferably defining a
generally annular undercut 8108. Alternatively, the protrusion 8106
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 8106 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0687] Preferably, the protrusion 8106 has a cross-sectional
configuration, as can be readily seen in FIG. 71B, which is
characterized in that an underlying surface portion 8110 of
protrusion 8106, at the undercut 8108, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
8112 of protrusion 8106.
[0688] It is a particular feature of the implantable artificial
acetabular socket 8100 that a lower portion 8120 of outer bone
engagement surface 8104 is formed with an inward groove 8122.
Inward groove 8122 is provided to allow for the growth of bone or
fibrous tissue following the implantation of acetabular socket 8100
and to promote biological fixation of acetabular socket 8100.
[0689] Reference is now made to FIGS. 72A, 72B, and 72C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a further preferred
embodiment of the present invention.
[0690] Preferably, implantable artificial acetabular socket 8200 is
of generally uniform thickness, is symmetric about an axis 8201 and
defines an hemispherical concave inner articulation surface 8202,
having a beveled edge 8203, and a generally hemispherical outer
bone engagement surface 8204, which preferably has formed thereon,
at any suitable location between its apex and its rim, a generally
annular outwardly extending protrusion 8206, preferably defining a
generally annular undercut 8208. Alternatively, the protrusion 8206
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 8206 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0691] Preferably, the protrusion 8206 has a cross-sectional
configuration, as can be readily seen in FIG. 72B, which is
characterized in that an underlying surface portion 8210 of
protrusion 8206, at the undercut 8208, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
8212 of protrusion 8206.
[0692] It is a particular feature of the implantable artificial
acetabular socket 8200 that a lower portion 8220 of outer bone
engagement surface 8204 is formed with multiple inward grooves
8222. Multiple inward grooves 8222 are provided to allow for the
growth of bone or fibrous tissue following the implantation of
acetabular socket 8200 and to promote biological fixation of
acetabular socket 8200.
[0693] Reference is now made to FIGS. 73A and 73B, which are
respective pictorial and sectional illustrations of an implantable
artificial femoral or humeral head resurfacing element constructed
and operative in accordance with still another preferred embodiment
of the present invention. The implantable artificial femoral or
humeral head resurfacing element is intended for mounting onto a
natural femoral or humeral head in accordance with a preferred
embodiment of the present invention.
[0694] As seen in FIGS. 73A and 73B, an implantable artificial
femoral or humeral head resurfacing element, designated by
reference numeral 8300, is formed preferably by injection molding
of polyurethane. Preferred polyurethane materials are described
hereinbelow.
[0695] Preferably, implantable artificial femoral or humeral head
resurfacing element 8300 is of generally uniform thickness, other
than at its apex which is thickened, is symmetric about an axis
8301 and defines an hemispherical outer articulation surface 8302
and a generally hemispherical inner bone engagement surface 8304,
having a beveled edge 8305, which preferably has formed thereon, at
any suitable location between its apex and its rim, a generally
annular inwardly extending protrusion 8306, preferably defining a
generally annular undercut 8308. Alternatively, the protrusion 8306
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 8306 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a femoral or humeral head.
[0696] Preferably, the protrusion 8306 has a cross-sectional
configuration, as can be readily seen in FIG. 73B, which is
characterized in that an underlying surface portion 8310 of
protrusion 8306, at the undercut 8308, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
8312 of protrusion 8306.
[0697] The outer articulation surface 8302 of implantable
artificial femoral or humeral head resurfacing element 8300
preferably includes a peripheral recess 8314, generally located
proximate to the edge of outer articulation surface 8302.
Preferably, radio opaque ring element 8316 is embedded in
peripheral recess 8314. Provision of radio opaque ring element 8316
provides the ability to monitor the position of artificial femoral
or humeral head resurfacing element 8300 after it has been
implanted. Radio opaque ring element 8316 is preferably comprised
of metal, barium sulfate, zirconium oxide or any other suitable
radio opaque material, and may be molded and inserted into
artificial femoral or humeral head resurfacing element 8300 or
integrally formed therewith.
[0698] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
femoral or humeral head resurfacing element 8300 at the apex
thereof, any suitable portion thereof may be of non-uniform
thickness.
[0699] It is appreciated that, even though the illustrated
embodiment shows the provision of a radio opaque ring element in a
femoral or humeral head, the provision of a radio opaque ring
element is not limited to a femoral or humeral head, but may be
included with any of the artificial implants described in this
application.
[0700] Reference is now made to FIGS. 74A and 74B, which are
respective pictorial and sectional illustrations of an implantable
artificial femoral or humeral head resurfacing element constructed
and operative in accordance with still another preferred embodiment
of the present invention. The implantable artificial femoral or
humeral head resurfacing element is intended for mounting onto a
natural femoral or humeral head in accordance with a preferred
embodiment of the present invention.
[0701] As seen in FIGS. 74A and 74B, an implantable artificial
femoral or humeral head resurfacing element, designated by
reference numeral 8400, is formed preferably by injection molding
of polyurethane. Preferred polyurethane materials are described
hereinbelow.
[0702] Preferably, implantable artificial femoral or humeral head
resurfacing element 8400 is of generally uniform thickness, other
than at its apex which is thickened, is symmetric about an axis
8401 and defines an hemispherical outer articulation surface 8402
and a generally hemispherical inner bone engagement surface 8404,
having a beveled edge 8405, which preferably has formed thereon, at
any suitable location between its apex and its rim, a generally
annular inwardly extending protrusion 8406, preferably defining a
generally annular undercut 8408. Alternatively, the protrusion 8406
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 8406 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a femoral or humeral head.
[0703] Preferably, the protrusion 8406 has a cross-sectional
configuration, as can be readily seen in FIG. 74B, which is
characterized in that an underlying surface portion 8410 of
protrusion 8406, at the undercut 8408, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
8412 of protrusion 8406.
[0704] The inner bone engagement surface 8404 of implantable
artificial femoral or humeral head resurfacing element 8400
preferably includes a peripheral recess 8414, generally located
proximate to the edge of inner bone engagement surface 8404.
Preferably, radio opaque ring element 8416 is embedded in
peripheral recess 8414 Provision of radio opaque ring element 8416
provides the ability to monitor the position of artificial femoral
or humeral head resurfacing element 8400 after it has been
implanted. Radio opaque ring element 8416 is preferably comprised
of metal, barium sulfate, zirconium oxide or any other suitable
radio opaque material, and may be molded and inserted into
artificial femoral or humeral head resurfacing element 8400 or
integrally formed therewith.
[0705] It is appreciated that, even though the illustrated
embodiment shows the non-uniform thickness portion of artificial
femoral or humeral head resurfacing element 8400 at the apex
thereof, any suitable portion thereof may be of non-uniform
thickness.
[0706] Reference is now made to FIGS. 75A and 75B, which are
respective pictorial and sectional illustrations of an implantable
artificial femoral or humeral head resurfacing element constructed
and operative in accordance with still another preferred embodiment
of the present invention. The implantable artificial femoral or
humeral head resurfacing element is intended for mounting onto a
natural femoral or humeral head in accordance with a preferred
embodiment of the present invention.
[0707] As seen in FIGS. 75A and 75B, an implantable artificial
femoral or humeral head resurfacing element, designated by
reference numeral 8500, is formed preferably by injection molding
of polyurethane. Preferred polyurethane materials are described
hereinbelow.
[0708] Preferably, implantable artificial femoral or humeral head
resurfacing element 8500 is of generally uniform thickness, other
than at its apex which is thickened, is symmetric about an axis
8501 and defines an hemispherical outer articulation surface 8502
and a generally hemispherical inner bone engagement surface 8504,
having a beveled edge 8505, which preferably has formed thereon, at
any suitable location between its apex and its rim, a generally
annular inwardly extending protrusion 8506, preferably defining a
generally annular undercut 8508. Alternatively, the protrusion 8506
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 8506 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a femoral or humeral head.
[0709] Preferably, the protrusion 8506 has a cross-sectional
configuration, as can be readily seen in FIG. 75B, which is
characterized in that an underlying surface portion 8510 of
protrusion 8506, at the undercut 8508, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
8512 of protrusion 8506.
[0710] An edge surface 8513 of implantable artificial femoral or
humeral head resurfacing element 8500 preferably includes a
peripheral recess 8514. Preferably, radio opaque ring element 8516
is embedded in peripheral recess 8514. Provision of radio opaque
ring element 8516 provides the ability to monitor the position of
artificial femoral or humeral head resurfacing element 8500 after
it has been implanted. Radio opaque ring element 8516 is preferably
comprised of metal, barium sulfate, zirconium oxide or any other
suitable radio opaque material, and may be molded and inserted into
artificial femoral or humeral head resurfacing element 8500 or
integrally formed therewith.
[0711] Reference is now made to FIGS. 76A and 76B, which are
respective pictorial and sectional illustrations of an implantable
artificial acetabular socket constructed and operative in
accordance with a preferred embodiment of the present invention and
which is particularly suitable for use in a hip joint.
[0712] As seen in FIGS. 76A and 76B, an implantable artificial
acetabular socket, designated by reference numeral 8600, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0713] Preferably, implantable artificial acetabular socket 8600 is
of generally uniform thickness, is symmetric about an axis 8601 and
defines an hemispherical concave inner articulation surface 8602
and a generally hemispherical outer bone engagement surface 8604,
which preferably has formed thereon, at any suitable location
between its apex and its rim, a generally annular outwardly
extending protrusion 8606, preferably defining a generally annular
undercut 8608. Alternatively, the protrusion 8606 may be any other
suitable non-annular, open or closed, generally peripheral,
protrusion. The protrusion 8606 is preferably arranged for snap-fit
engagement with a corresponding groove formed by reaming of a bone,
examples of which are described hereinabove.
[0714] Preferably, the protrusion 8606 has a cross-sectional
configuration, as can be readily seen in FIG. 76B, which is
characterized in that an underlying surface portion 8610 of
protrusion 8606, at the undercut 8608, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
8612 of protrusion 8606.
[0715] It is a particular feature of the implantable artificial
acetabular socket 8600 that a portion of outer bone engagement
surface 8604 thereof defines a thickened portion 8614, preferably
extending from a location generally adjacent protrusion 8606.
Thickened portion 8614 is preferably molded to correspond with the
shape of the acetabular notch. Thickened portion 8614 is provided
to add stability to acetabular socket 8600 once implanted, by
minimizing rotational movement and preventing rotational
dislodgment.
[0716] Reference is now made to FIGS. 77A and 77B, which are
respective pictorial and sectional illustrations of an implantable
artificial acetabular socket constructed and operative in
accordance with a preferred embodiment of the present invention and
which is particularly suitable for use in a hip joint.
[0717] As seen in FIGS. 77A and 77B, an implantable artificial
acetabular socket, designated by reference numeral 8700, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0718] Preferably, implantable artificial acetabular socket 8700 is
of generally uniform thickness, is symmetric about an axis 8701 and
defines an hemispherical concave inner articulation surface 8702
and a generally hemispherical outer bone engagement surface 8704,
which preferably has formed thereon, at any suitable location
between its apex and its rim, a generally annular outwardly
extending protrusion 8706, preferably defining a generally annular
undercut 8708. Alternatively, the protrusion 8706 may be any other
suitable non-annular, open or closed, generally peripheral,
protrusion. The protrusion 8706 is preferably arranged for snap-fit
engagement with a corresponding groove formed by reaming of a bone,
examples of which are described hereinabove.
[0719] Preferably, the protrusion 8706 has a cross-sectional
configuration, as can be readily seen in FIG. 77B, which is
characterized in that an underlying surface portion 8710 of
protrusion 8706, at the undercut 8708, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
8712 of protrusion 8706.
[0720] As seen in FIGS. 77A and 77B, implantable artificial
acetabular socket 8700 is a less than full hemispherical, low
profile acetabular socket, as can be readily seen from radius 8714,
which shows a radius of the full hemispherical socket that
acetabular socket 8700 is similar to. Acetabular socket 8700 thus
provides for implantation with less reaming of bone required.
[0721] Reference is now made to FIGS. 78A and 78B, which are
respective pictorial and sectional illustrations of an implantable
artificial acetabular socket constructed and operative in
accordance with a preferred embodiment of the present invention and
which is particularly suitable for use in a hip joint.
[0722] As seen in FIGS. 78A and 78B, an implantable artificial
acetabular socket, designated by reference numeral 8800, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0723] Preferably, implantable artificial acetabular socket 8800 is
of generally uniform thickness, is symmetric about an axis 8801 and
defines an hemispherical concave inner articulation surface 8802
and a generally hemispherical outer bone engagement surface 8804,
which preferably has formed thereon, at any suitable location
between its apex and its rim, a generally annular outwardly
extending protrusion 8806, preferably defining a generally annular
undercut 8808. Alternatively, the protrusion 8806 may be any other
suitable non-annular, open or closed, generally peripheral,
protrusion. The protrusion 8806 is preferably arranged for snap-fit
engagement with a corresponding groove formed by reaming of a bone,
examples of which are described hereinabove
[0724] Preferably, the protrusion 8806 has a cross-sectional
configuration, as can be readily seen in FIG. 78B, which is
characterized in that an underlying surface portion 8810 of
protrusion 8806, at the undercut 8808, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
8812 of protrusion 8806.
[0725] Implantable artificial acetabular socket 8800 also includes
an extended portion 8820, preferably provided to prevent
dislocation of the femoral head following insertion.
[0726] Reference is now made to FIGS. 79A and 79B, which are
respective pictorial and sectional illustrations of an implantable
artificial acetabular socket constructed and operative in
accordance with a preferred embodiment of the present invention and
which is particularly suitable for use in a hip joint.
[0727] As seen in FIGS. 79A and 79B, an implantable artificial
acetabular socket, designated by reference numeral 8900, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0728] Preferably, implantable artificial acetabular socket 8900 is
of generally uniform thickness, is symmetric about an axis 8901 and
defines an hemispherical concave inner articulation surface 8902
and a generally hemispherical outer bone engagement surface 8904,
which preferably has formed thereon, at any suitable location
between its apex and its rim, a generally annular outwardly
extending protrusion 8906, preferably defining a generally annular
undercut 8908. Alternatively, the protrusion 8906 may be any other
suitable non-annular, open or closed, generally peripheral,
protrusion. The protrusion 8906 is preferably arranged for snap-fit
engagement with a corresponding groove formed by reaming of a bone,
examples of which are described hereinabove.
[0729] Preferably, the protrusion 8906 has a cross-sectional
configuration, as can be readily seen in FIG. 79B, which is
characterized in that an underlying surface portion 8910 of
protrusion 8906, at the undercut 8908, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
8912 of protrusion 8906.
[0730] It is a particular feature of the implantable artificial
acetabular socket 8900 that protrusion 8906 is arranged such that
it is not orthogonal to axis 8901 and thus allows proper
orientation of the artificial acetabular socket in an improperly
reamed natural acetabulum. Implantable artificial acetabular socket
8900 is provided with protrusion 8906 for engagement with a reamed
acetabulum, where the reaming was performed in a less than
desirable orientation.
[0731] Reference is now made to FIGS. 80A, 80B, and 80C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a preferred embodiment
of the present invention and which is particularly suitable for use
in a hip joint.
[0732] As seen in FIGS. 80A, 80B and 80C, an implantable artificial
acetabular socket, designated by reference numeral 9000, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0733] Preferably, implantable artificial acetabular socket 9000 is
of generally uniform thickness, is symmetric about an axis 9001 and
defines an hemispherical concave inner articulation surface 9002,
having a beveled edge 9003, and a generally hemispherical outer
bone engagement surface 9004, which preferably has formed thereon,
at any suitable location between its apex and its rim, a generally
annular outwardly extending protrusion 9006, preferably defining a
generally annular undercut 9008. Alternatively, the protrusion 9006
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 9006 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0734] Preferably, the protrusion 9006 has a cross-sectional
configuration, as can be readily seen in FIG. 80B, which is
characterized in that an underlying surface portion 9010 of
protrusion 9006, at the undercut 9008, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
9012 of protrusion 9006.
[0735] It is a particular feature of the implantable artificial
acetabular socket 9000 that a portion of outer bone engagement
surface 9004, preferably the portion located between protrusion
9006 and the apex thereof, includes a plurality of hollow annular
protrusions 9020 integral with surface 9004 but protruding beyond
surface 9004. Annular protrusions 9020 are shaped with an undercut
and are in contact with prepared acetabulum leaving a gap between
the prepared acetabular surface and implant surface 9004. Annular
protrusions 9020 provide localized areas of low contact area and
thus high localized stress. With time, the high localized stress
allows controlled subsidence of the implant until surface 9004
comes into contact with the acetabular bone surface. The controlled
subsidence of the implant also enables the bony surface to
completely surround the undercut shape of annular protrusions 9020,
thus further improving the fixation of the implant.
[0736] Reference is now made to FIGS. 81A, 81B, and 81C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a preferred embodiment
of the present invention and which is particularly suitable for use
in a hip joint.
[0737] As seen in FIGS. 81A, 81B and 81C, an implantable artificial
acetabular socket, designated by reference numeral 9100, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0738] Preferably, implantable artificial acetabular socket 9100 is
of generally uniform thickness, is symmetric about an axis 9101 and
defines an hemispherical concave inner articulation surface 9102,
having a beveled edge 9103, and a generally hemispherical outer
bone engagement surface 9104, which preferably has formed thereon,
at any suitable location between its apex and its rim, a generally
annular outwardly extending protrusion 9106, preferably defining a
generally annular undercut 9108. Alternatively, the protrusion 9106
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 9106 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0739] Preferably, the protrusion 9106 has a cross-sectional
configuration, as can be readily seen in FIG. 81B, which is
characterized in that an underlying surface portion 9110 of
protrusion 9106, at the undercut 9108, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
9112 of protrusion 9106.
[0740] It is a particular feature of the implantable artificial
acetabular socket 9100 that a portion of outer bone engagement
surface 9104, preferably the portion located between protrusion
9106 and the apex thereof, includes a plurality of annular recesses
9120 enclosing annular protrusions 9122. Annular protrusions 9122
are designed with an undercut and are in contact with prepared
acetabulum leaving a gap between the prepared acetabular surface
and implant surface 9104. Annular protrusions 9122 provide
localized areas of low contact area and thus high localized stress.
With time, the high localized stress allows controlled subsidence
of the implant until implant surface 9104 comes into contact with
the acetabular bone surface. The controlled subsidence of the
implant also enables bone or fibrous tissue to completely fill in
the annular recesses 9120 and undercut of annular protrusion 9122
to further stabilize the implant in place through biological
fixation.
[0741] Reference is now made to FIGS. 82A, 82B, and 82C, which are
respective pictorial, sectional and partially cut away
illustrations of an implantable artificial acetabular socket
constructed and operative in accordance with a preferred embodiment
of the present invention and which is particularly suitable for use
in a hip joint.
[0742] As seen in FIGS. 82A, 82B and 82C, an implantable artificial
acetabular socket, designated by reference numeral 9200, is formed
preferably by injection molding of polyurethane. Preferred
polyurethane materials are described hereinbelow.
[0743] Preferably, implantable artificial acetabular socket 9200 is
of generally uniform thickness, is symmetric about an axis 9201 and
defines an hemispherical concave inner articulation surface 9202,
having a beveled edge 9203, and a generally hemispherical outer
bone engagement surface 9204, which preferably has formed thereon,
at any suitable location between its apex and its rim, a generally
annular outwardly extending protrusion 9206, preferably defining a
generally annular undercut 9208. Alternatively, the protrusion 9206
may be any other suitable non-annular, open or closed, generally
peripheral, protrusion. The protrusion 9206 is preferably arranged
for snap-fit engagement with a corresponding groove formed by
reaming of a bone, examples of which are described hereinabove.
[0744] Preferably, the protrusion 9206 has a cross-sectional
configuration, as can be readily seen in FIG. 82B, which is
characterized in that an underlying surface portion 9210 of
protrusion 9206, at the undercut 9208, defines a slope which is
sharper than a corresponding slope of an overlying surface portion
9212 of protrusion 9206.
[0745] It is a particular feature of the implantable artificial
acetabular socket 9200 that a portion of outer bone engagement
surface 9204, preferably the portion located between protrusion
9206 and the apex thereof, includes a plurality of annular
protrusions 9220. Annular protrusions 9220 are preferably arranged
for engagement with corresponding recesses formed by reaming of a
bone, to provide enhanced biological fixation of acetabular socket
9200 following insertion thereof.
[0746] Reference is now made to FIG. 83, which is a pictorial
illustration of an implantable artificial acetabular socket 9300,
constructed and operative in accordance with another preferred
embodiment of the present invention, which is particularly suitable
for use in a hip joint. Implantable artificial acetabular socket
9300 is constructed with a textured thin element 9302, preferably
made of titanium, with an annular configuration, molded onto an
outer surface 9304 of acetabular socket 9300. The provision of
element 9302 provides enhanced biological fixation of acetabular
socket 9300 following insertion thereof. It is appreciated that
element 9302 may cover the entire surface 9304 or any suitable
portion thereof.
[0747] Reference is now made to FIG. 84, which is a pictorial
illustration of an implantable artificial acetabular socket 9400,
constructed and operative in accordance with another preferred
embodiment of the present invention, which is particularly suitable
for use in a hip joint. Implantable artificial acetabular socket
9400 is constructed with an array 9402 of textured thin elements
9404, preferably made of titanium, with segmented configuration,
molded onto outer surface 9406 of acetabular socket 9400. The
provision of elements 9404 provides enhanced biological fixation of
acetabular socket 9400 following insertion thereof. It is
appreciated that, even though the illustrated embodiment shows
elements 9404 having a square configuration arranged symmetrically,
elements 9404 may have any suitable shape and arrangement.
[0748] Reference is now made to FIGS. 85A and 85B, which are
sectional illustrations of the installation of an artificial
femoral resurfacing head on a reamed femoral head, in accordance
with a preferred embodiment of the present invention. As seen in
FIG. 85A, femoral head 9500 has been reamed to define a seating
location 9502, preparatory to the placement of a press fit femoral
head resurfacing element 9504. FIG. 85B shows element 9504
following placement thereof on reamed femoral head 9500.
[0749] Reference is now made to FIGS. 86A and 86B, which are
sectional illustrations of the installation of an artificial
femoral resurfacing head on a reamed femoral head, in accordance
with a preferred embodiment of the present invention. As seen in
FIG. 86A, femoral head 9510 has been reamed to define a seating
location 9512, preparatory to the placement of a snap fit femoral
head resurfacing element 9514. FIG. 86B shows element 9514
following placement thereof on reamed femoral head 9510.
[0750] Reference is now made to FIGS. 87A, 87B, 87C and 87D, which
are sectional illustrations of various stages of installation of a
multi-part artificial femoral resurfacing head on a reamed femoral
head in accordance with still another preferred embodiment of the
present invention. As seen in FIG. 87A, femoral head 9520 has been
reamed to define a seating location 9522, preparatory to the
placement of a snap fit femoral head interface element 9524. FIG.
87B shows element 9524, preferably made of polyurethane, following
placement thereof on reamed femoral head 9520. FIG. 87C shows the
femoral head of FIG. 87B, preparatory to the placement of a press
fit femoral head resurfacing element 9526. Press fit femoral head
resurfacing element 9526 is made of any suitable bearing surface
materials, such as polyurethane, metal or ceramic. FIG. 87D shows
element 9526 following placement thereof on femoral head interface
element 9524.
[0751] Reference is now made to FIGS. 88A, 88B, 88C and 88D, which
are sectional illustrations of various stages of installation of a
multi-part artificial femoral resurfacing head on a reamed femoral
head in accordance with still another preferred embodiment of the
present invention. As seen in FIG. 88A, femoral head 9530 has been
reamed to define a seating location 9532, preparatory to the
placement of a snap fit femoral head interface element 9534. FIG.
88B shows element 9534, preferably made of polyurethane, following
placement thereof on reamed femoral head 9530. FIG. 88C shows the
femoral head of FIG. 88B, preparatory to the placement of a press
fit femoral head resurfacing element 9536. Press fit femoral head
resurfacing element 9536 is made of any suitable hearing surface
materials, such as polyurethane, metal or ceramic. FIG. 88D shows
element 9536 following placement thereof on femoral head interface
element 9534.
[0752] Reference is now made to FIGS. 89A and 89B, which are
sectional illustrations of various stages of installation of a
multi-part artificial femoral resurfacing head on a reamed femoral
head in accordance with still another preferred embodiment of the
present invention. As seen in FIG. 89A, femoral head 9540 has been
reamed to define a seating location 9542, preparatory to the
placement of a press fit femoral head interface element 9544. Press
fit femoral head interface element 9544 may be made of
polyurethane, metal or any other suitable material. FIG. 89B shows
element 9544, following placement thereof on reamed femoral head
9540 and the placement of a press fit femoral head resurfacing
element 9546 thereon. Press fit femoral head resurfacing element
9546 is preferably made of any suitable bearing surface materials
such as polyurethane, metal or ceramic.
[0753] It is appreciated that the embodiments shown in FIGS.
85A-89B allow for a variety of combinations of snap fit and press
fit femoral head interface elements and resurfacing elements. These
elements may be comprised of different substances, to provide
suitable rigidity and flexibility of the articulation surface, as
well as suitable configurations for implantation. Generally, the
snap fit devices provide for more flexibility, and are formed
preferably by injection molding of polyurethane, while the press
fit devices generally provide more rigidity, and may be formed by
injection molding of polyurethane, or may be formed from any other
suitable material, such as metal or ceramic, by any suitable
method. Additionally, resurfacing elements 9526, 9536 and 9546,
described in reference to FIGS. 87A-89B, may be molded or sprayed
directly onto interface elements 9524, 9534 or 9544, respectively,
or may be formed by dipping onto interface elements 9524, 9534 or
9544, prior to their implantation on machined femoral head 9520,
9530 or 9540, respectively.
[0754] Reference is now made to FIG. 90A, which is a sectional
illustration of a femoral head in accordance with another preferred
embodiment of the present invention. As seen in FIG. 90A, femoral
head 9600 has been fitted with a conventional femoral stem 9602. An
artificial femoral head element 9604 is mounted onto stem 9602.
Artificial femoral head element 9604 includes an articulation
element 9606, preferably formed of polyurethane, overlying a rigid
metal core element 9608, which also includes a tapered trunnion for
mounting core element 9608 onto conventional stem 9602. Core
element 9608 may be constructed of metal, ceramic or any other
rigid material, and is preferably less flexible than articulation
element 9606. Articulation element 9606 may be mounted or formed
onto core element 9608 by spraying, dipping, injection or blow
molding or formed separately by any suitable means and assembled
thereafter onto core element 9608.
[0755] Reference is now made to FIG. 90B, which is a sectional
illustration of a humeral head in accordance with another preferred
embodiment of the present invention. As seen in FIG. 90B, humeral
head 9650 has been fitted with a conventional humeral stem 9652. An
artificial humeral head element 9654 is mounted onto stem 9652.
Artificial humeral head element 9654 includes an articulation
element 9656, preferably formed of polyurethane, overlying a rigid
metal core element 9658, which also includes a tapered trunnion for
mounting core element 9658 onto conventional stem 9652. Core
element 9658 may be constructed of metal, ceramic or any other
rigid material, and is preferably less flexible than articulation
element 9656. Articulation element 9656 may be mounted or formed
onto core element 9658 by spraying, dipping, injection or blow
molding or formed separately by any suitable means and assembled
thereafter onto core element 9658.
[0756] It is further appreciated that femoral and humeral heads of
FIGS. 90A-90B could be resurfacing implants positioned directly to
a suitably prepared natural femoral or humeral head without a
conventional stem.
[0757] Reference is now made to FIGS. 91A, 91B and 91C, which are
sectional illustrations showing bone growth adjacent to an
implanted acetabular socket in accordance with another preferred
embodiment of the present invention. As seen in FIG. 91A, an
acetabular socket 9700, similar to acetabular socket 9100 of FIGS.
81A-81C, is implanted in reamed acetabulum 9702. Acetabular socket
9700 includes recesses 9704. As seen in FIG. 91A, over time the
acetabulum has remodeled itself to fill recesses 9704. As seen in
FIGS. 91B and 91C, different shaped recesses may be provided along
acetabular socket 9700. It is appreciated that the configuration
pattern of recesses 9704 of the bone engagement surface 9706
provides enhanced adhesion of acetabulum 9702 to socket 9700 and
thus improves the stability of socket 9700. This configuration
pattern could apply to any of the implant devices disclosed
herein.
[0758] Reference is now made to FIG. 92, which is a simplified
sectional illustration of a bone engagement surface, textured in
accordance with another preferred embodiment of the present
invention. The bone engagement surface of FIG. 92 provides enhanced
bone adhesion and improved stability.
[0759] As seen in FIG. 92, a portion of an artificial implantation
device 9800, such as acetabular sockets described hereinabove, but
not limited to acetabular sockets, having a bone engagement surface
9802, engages bone 9804. Bone engagement surface 9802 includes a
rough texture 9806 superimposed on to at least a portion thereof.
It is appreciated that bone engagement surface 9802 may be uniform,
such as surface 1104 in socket 1100 shown in FIGS. 1A-1C, or may
include various protrusions or recesses, such as surface 9104 in
socket 9100 of FIGS. 81A-81C. Over time, bone cells, fibroblasts
and tissue matrix 9808 fill the crevices of rough texture 9806
along surface 9802, as shown in FIG. 92.
[0760] Reference is now made to FIGS. 93A and 93B, which are
simplified pictorial illustrations of a method of modifying the
texture of a bone engagement surface of an artificial implantation
device, in accordance with another preferred embodiment of the
present invention.
[0761] FIG. 93A illustrates a method for modifying the surface of
the artificial implantation device 9900, by mechanically providing
surface roughness, such as by grit blasting. Grit blasting may be
conducted without any preparatory steps, other than cleaning the
contact surface 9902 of implantation device 9900. Grit blasting can
be accomplished with any suitable media capable of creating a
texturized surface. If a non medical grade media is used then
residual is preferably cleaned from the implant surface to prevent
initiation of a foreign body reaction. Alternatively, grit blasting
may utilize Hydroxylapatite or any other bioactive materials as the
grit media 9904. Artificial implantation device 9900 is rotated
around its axis, as indicated by arrow 9906, and the blast nozzle
9908 will be generally positioned at a right angle to the rotating
part.
[0762] Grit blasting may be hot grit blasting, utilizing heated
gas. A heating cycle, which is meant to soften the outer layers of
the artificial implantation device 9900, will precede the blasting
phase in order to help embed the bioactive particles of grit media
9904 into the surface 9902 of artificial implantation device 9900.
Since the bioactive particles of grit media 9904 are harder than
the heated surface 9902, particles will become embedded into
surface 9902. This process will form a roughened texture that will
act as the anchor for bone attachment. In addition, the resorption
of the Hydroxylapatite with time will cause bone growth into the
voids that are created by the resorption of the grit media. FIG.
93B shows the grit media 9902 implanted into contact surface 9902
of artificial implantation device 9900.
[0763] Reference is now made to FIG. 94, which is a simplified
pictorial illustration of another method of modifying the texture
of the bone engagement surface of an artificial implantation
device, in accordance with yet another preferred embodiment of the
present invention.
[0764] As seen in FIG. 94, contact surface 9950 of artificial
implantation device 9952 is treated to provide surface roughness
and surface porosity by forming at least one additional layer 9954
of sprayed material 9956. The spraying apparatus, described
hereinbelow with reference to FIG. 95, may use feedstock configured
as a rod or provided as powder. The feedstock rod or powder may be
a neat elastomer, preferably of an equal or similar type of
elastomer to the material from which artificial implantation device
is formed therefrom, such as polyurethane. The feedstock rod may be
extruded from a premix of an elastomer and Bioactive materials.
[0765] The surface roughness and surface porosity is provided
preferably by co-spraying of an elastomer and bioactive materials
composite coating. The premixed feedstock may be PU/HA
(polyurethane/Hydroxylapatite), thus providing a co-spraying of
PU/HA composite coating. The bioactive materials are preferably
hydroxylapatite or any other suitable calcium phosphate-containing
materials. These bioactive materials cause the contact surface 9950
of artificial implantation device 9952 to become bioactive,
stimulating bone growth to provide an adhesion of the implant to
the bone and accelerate osteointegration.
[0766] The feedstock for this coating can be in powder form, where
a combination of PU and HA powders are preferably blended in
suitable ratios and sprayed to form the desired coating.
Alternatively, the feedstock can be a PU rod that is co-sprayed
with HA powder particles that are fed separately into the molten
particle flow. The PU rod can also be extruded with HA powder mixed
within it so that a composite rod feedstock is obtained.
Alternatively, any other suitable method of combining the PU and
the bioactive materials may be used. The rod will then be fed
directly though the spray device and the resulting coating will
contain both HA and PU particles forming the desired matrix.
[0767] Reference is now made to FIG. 95, which is a simplified
pictorial illustration of a spraying apparatus which may be used in
the embodiment of FIG. 94.
[0768] As seen in FIG. 95, spraying apparatus 9960 is used, as
described hereinabove with reference to FIG. 94, to modify the
contact surface 9950 of artificial implantation device 9952 by
coating contact surface 9950. This coating is preferably provided
using a combustion process, which utilizes an oxygen-fuel mixture
and heats the particles as they are fed through a gravity hopper
through the center of the spraying apparatus 9960. A nozzle 9964
directs the combustion gasses and the molten particles towards the
contact surface 9950 of artificial implantation device 9952. The
combustion of the gasses occurs within a chamber in the nozzle and
a carrier gas is used to propel the molten particles forward, in
the direction of arrows 9970, and prevent them from sticking to the
nozzle walls. When using rod feedstock (in place of powder),
atomizing gas is used to break the tip of the molten rod into
discrete particles.
[0769] A coating of molten polyurethane particles can be applied to
contact surface 9950 of artificial implantation device 9952 in
order to create a rough porous surface into which the bone can
grow. The process may start with a preheating step that is designed
to melt the surface of the implant and provide for a chemical bond
between the surface and the polyurethane particles, although the
process can be applied to a cold surface as well. The thickness of
the coating can be regulated.
[0770] The coating deposited using the above mentioned combustion
spray process may be a Polymer-Hydroxylapatite composite coating.
This coating system consists of a combination of polyurethane
particles that will be co-sprayed with HA powder The resulting
coating will form a polymer scaffold like structure that will
entrap the HA particles within. This composite structure will help
anchor the implant by enabling bone attachment to the exposed HA
particles and eventually bone interdigitation in the pores created
as the HA resorbs with time.
[0771] Alternatively, a coating can be deposited onto the contact
surface 9950 of artificial implantation device 9952 by means of
dipping, whereby a slurry is made of a polymer material, having a
certain quantity of bioactive particles mixed within it. The
artificial implantation device 9952 is dipped into the slurry,
after which it is allowed to dry. As the slurry dries, a composite
polymer/bioactive material coating is created, where the bioactive
particles are trapped within the polymer matrix.
[0772] The coating may be an elastomer on elastomer coating, such
as a polyurethane on polyurethane coating. The polyurethane coating
can have a hardness of 55 D and upwards for enhancing bio-stability
on the outer surface, while the artificial implantation device 9952
and contact surface 9950 is of hardness 80 A.
[0773] In addition to the enhanced bone adhesion methods described
in reference to FIGS. 91A-95, the contact surface of an artificial
implantation device may also be treated using one of the following
Surface Modification processes: Atomic cleaning, adhesion
promotion, molecular grafting, cell attachment enhancement, and
Plasma Enhanced Chemical Vapor Deposition (PECVD) coatings, such as
implemented by the MetroLine Surface. Inc. Surface modification
processes improve the articulating properties of the contact
surface by reducing friction and thereby enhance the resistance to
wear.
[0774] It is known in the art that in the vicinity of rigid
implants, such as metal implants, there are regions of stress
shielding in some parts of the bone, meaning that such rigid
implants take load formerly transferred to the bone, thereby
shielding the bone from the load and causing bone resorption. This
process has been observed in regions such as in the proximal medial
calcar after hip replacement, and such as under the tibial
component of knee replacements.
[0775] The implants of the present invention comprise flexible
elements, and also preferably include deformation control elements,
resulting in improved load distribution, which prevents or
significantly reduces stress shielding.
[0776] As discussed hereinabove, it is appreciated that the
stresses produced in the natural bone, such as in the natural
acetabular socket, produce corresponding strains therein. Both the
stresses and the strains have positive medical implications which
are expressed in bone remodeling.
[0777] It is further appreciated that the implants of the present
invention are constructed to control the stress distribution at the
bone-implant interface, and within the surrounding bone, resulting
in a positive bone remodeling, creating a mechanical environment
with conditions that initiate net remodeling activity growing new
bone cells of structural characteristics. This process prevents
loosening of the devices according to this invention and enhances
the anchoring.
[0778] The following is a brief description of a best mode
manufacturing process of the implantable artificial socket 1100
shown in FIGS. 1A to 1C. The manufacturing process typically
comprises the steps as described hereinbelow. It is appreciated
that the steps of the manufacturing process are monitored and
controlled in order to assure the quality of the products meets the
required standards.
Step 1. Material Identification:
[0779] A preferable material used for manufacturing a cup used for
preparing the implantable artificial socket 1100 is Polycarbonate
Urethane Bionate 80A, which is supplied by Polymer Technology Group
Inc., 2810 7.sup.th Street, Berkeley, Calif. 94710, U.S.A.
Step 2. Equipment Used for Cup Manufacturing:
Step 2.1. Equipment Use for Pre-Injection Drying:
[0780] A desiccant that has the ability to be connected directly to
the screw of an injection molding machine and reach 50 deg dew
point, is preferably used.
Step 2.2. Equipment Use for Cup Injection:
[0781] The injection molding machine includes computerized data
acquisition ability and an 18-20 mm diameter cylinder, for example
an ARBURG 4020 device.
Step 2.3. Equipment Use for Post-Injection Curing:
[0782] Industrial oven capable of maintaining 80.degree.
C..+-.2.degree. C. for approximately 15 hours.
Step 3. Preprocess for the Raw Material:
[0783] The drying of the raw material is performed using a
desiccant dehumidifier, outside of a clean room.
Step 3.1. The Drying Process Typically Includes the Steps:
[0784] I. 12 hours at 65.degree. C. [-50 dew point] [0785] II. 4
hours at 93.degree. C. [-50 dew point]
[0786] The final product humidity should be preferably between
0.01%-0.02%.
Step 4. The Manufacturing Process:
[0787] 1. Drying of the material for 16 hours by special drier
(-50.degree. C.) desiccant. [0788] 2. Direct transfer of the
material in the drier to the injection machine, i.e. connecting a
drier device directly to the machine. [0789] 3. Injection molding.
[0790] 4. Curing in an oven for 16 hours. [0791] 5. Packaging.
[0792] 6. Sterilization in Gamma.
[0793] Preferred polyurethane materials for use in the embodiments
described hereinabove include the following materials.
[0794] The following materials are manufactured by POLYMER
TECHNOLOGY GROUP PTG.
[0795] Bionate.RTM. polycarbonate-urethane is among the most
extensively tested biomaterials ever developed. The Polymer
Technology Group Incorporated acquired the license to manufacture
this thermoplastic elastomer from Corvita Corporation (who marketed
it under the name Corethane.RTM.) in 1996.
[0796] Carbonate linkages adjacent to hydrocarbon groups give this
family of materials oxidative stability, making these polymers
attractive in applications where oxidation is a potential mode of
degradation, such as in pacemaker leads, ventricular assist
devices, catheters, stents, and many other biomedical devices.
Polycarbonate urethanes were the first biomedical polyurethanes
promoted for their biostability.
[0797] Bionate.RTM. polycarbonate-urethane is a thermoplastic
elastomer formed as the reaction product of a hydroxyl terminated
polycarbonate, an aromatic diisocyanate, and a low molecular weight
glycol used as a chain extender.
[0798] The scope of Bionate PCU's tests--encompassing Histology,
Carcinogenicity, Biostability, and Tripartite Biocompatiblity
Guidance for Medical Devices--reassures medical device and implant
manufacturers of the material's biocompatibility. This allows
biomaterials decision makers the ability to choose an efficacious
biomaterial that will add to the cost-effectiveness of the
development of their device or implant. Below is a summary of the
extensive biocompatibility testing conducted on Bionate PCUs,
including its successful completion of a 2-year carcinogenicity
study.
[0799] Copolymers of silicone with polyurethanes: [0800] PurSil.TM.
Silicone Polyether Urethane [0801] CarboSil.TM. Silicone
Polycarbonate Urethane
[0802] Silicones have long been known to be biostable and
biocompatible in most implants, and also frequently have the low
hardness and low modulus useful for many device applications.
Conventional silicone elastomers can have very high ultimate
elongations, but only low to moderate tensile strengths.
Consequently, the toughness of most biomedical silicone elastomers
is not particularly high. Another disadvantage of conventional
silicone elastomers in device manufacturing is the need for
cross-linking to develop useful properties. Once cross-linked, the
resulting thermoset silicone cannot be redissolved or remelted.
[0803] In contrast, conventional polyurethane elastomers are
generally thermoplastic with excellent physical properties.
Thermoplastic urethane elastomers (TPUs) combine high elongation
and high tensile strength to form tough, albeit fairly high-modulus
elastomers. Aromatic polyether TPUs can have excellent flex life,
tensile strength exceeding 5000 psi, and ultimate elongations
greater than 700 percent. They are often used for continuously
flexing, chronic implants such as ventricular-assist devices,
intraaortic balloons, and artificial heart components. TPUs can
easily be processed by melting or dissolving the polymer to
fabricate it into useful shapes.
[0804] The prospect of combining the biocompatibility and
biostability of conventional silicone elastomers with the
processability and toughness of TPUs is an attractive approach to
what would appear to be a nearly ideal biomaterial. For instance,
it has been reported that silicone acts synergistically with both
polycarbonate- and polyether-based polyurethanes to improve in vivo
and in vitro stability. In polycarbonate-based polyurethanes,
silicone copolymerization has been shown to reduce hydrolytic
degradation of the carbonate linkage, whereas in polyether
urethanes, the covalently bonded silicone seems to protect the
polyether soft segment from oxidative degradation in vivo.
[0805] PTG synthesized and patented silicone-polyurethane
copolymers by combining two previously reported methods:
copolymerization of silicone (PSX) together with organic
(non-silicone) soft segments into the polymer backbone, and the use
of surface-modifying end groups to terminate the copolymer chains.
Proprietary synthesis methods make high-volume manufacturing
possible.
[0806] PurSil.TM. silicone-polyether-urethane and CarboSil.TM.
silicone-polycarbonate-urethane are true thermoplastic copolymers
containing silicone in the soft segment. These high-strength
thermoplastic elastomers are prepared through a multi-step bulk
synthesis where polydimethylsiloxane (PSX) is incorporated into the
polymer soft segment with polytetramethyleneoxide (PTMO) (PurSil)
or an aliphatic, hydroxyl-terminated polycarbonate (CarboSil). The
hard segment consists of an aromatic diisocyanate, MDI, with a low
molecular weight glycol chain extender. The copolymer chains are
then terminated with silicone (or other) Surface-Modifying End
Groups.TM.. We also offer aliphatic (AL) versions of these
materials, with a hard segment synthesized from an aliphatic
diisocyanate.
[0807] Many of these silicone urethanes demonstrate previously
unavailable combinations of physical properties. For example,
aromatic silicone polyetherurethanes have a higher modulus at a
given shore hardness than conventional polyether urethanes--the
higher the silicone content, the higher the modulus (see PurSil
Properties). Conversely, the aliphatic silicone polyetherurethanes
have a very low modulus and a high ultimate elongation typical of
silicone homopolymers or even natural rubber (see PurSil AL
Properties). This makes them very attractive as high-performance
substitutes for conventional cross-linked silicone rubber. In both
the PTMO and PC families, certain polymers have tensile strengths
three to five times higher than conventional silicone
biomaterials.
[0808] Surface Modifying End Groups.TM. (SMEs) are surface-active
oligomers covalently bonded to the base polymer during synthesis.
SMEs--which include silicone (S), sulfonate (SO), fluorocarbon (F),
polyethylene oxide (P), and hydrocarbon (H) groups--control surface
chemistry without compromising the bulk properties of the polymer.
The result is key surface properties, such as thromboresistance,
biostability, and abrasion resistance, are permanently enhanced
without additional post-fabrication treatments or topical coatings.
This patented technology is applicable to a wide range of PTG's
polymers.
[0809] SMEs provide a series of (biomedical) base polymers that can
achieve a desired surface chemistry without the use of additives.
Polyurethanes prepared according to PTG's development process
couple endgroups to the backbone polymer during synthesis via a
terminal isocyanate group, not a hard segment. The added mobility
of endgroups relative to the backbone is thought to facilitate the
formation of uniform overlayers by the surface-active (end) blocks.
The use of the surface active endgroups leaves the original polymer
backbone intact so the polymer retains strength and processability.
The fact that essentially all polymer chains carry the
surface-modifying moiety eliminates many of the potential problems
associated with additives.
[0810] The SME approach also allows the incorporation of mixed
endgroups into a single polymer. For example, the combination of
hydrophobic and hydrophilic endgroups gives the polymer amphipathic
characteristics in which the hydrophobic versus hydrophilic balance
may be easily controlled.
[0811] The following Materials are manufactured by CARDIOTECH
CTE:
[0812] CHRONOFLEX.RTM.: Biodurable Polyurethane Elastomers are
polycarbonate aromatic polyurethanes.
[0813] The ChronoFlex.RTM. family of medical-grade segmented
polyurethane elastomers have been specifically developed by
CardioTech International to overcome the in vivo formation of
stress-induced microfissures.
[0814] HYDROTHANE.TM.: Hydrophilic Thermoplastic Polyurethanes
[0815] HydroThane.TM. is a family of super-adsorbent,
thermoplastic, polyurethane hydrogels, ranging in water content
from 5 to 25% by weight, HydroThane.TM. is offered as a clear resin
in durometer hardness of 80 A and 93 Shore A.
[0816] The outstanding characteristic of this family of materials
is the ability to rapidly absorb water, high tensile strength, and
high elongation. The result is a polymer having some lubricious
characteristics, as well as being inherently bacterial resistant
due to their exceptionally high water content at the surface.
[0817] HydroThane.TM. hydrophilic polyurethane resins are
thermoplastic hydrogels, and can be extruded or molded by
conventional means. Traditional hydrogels on the other hand are
thermosets and difficult to process.
[0818] The following materials are manufactured by THERMEDICS:
[0819] Tecothane.RTM. (aromatic polyether-based polyurethane),
Carbothane.RTM. (aliphatic polycarbonate-based polyurethane),
Tecophilic.RTM. (high moisture absorption aliphatic polyether-based
polyurethane) and Tecoplast.RTM. (aromatic polyether-based
polyurethane).
[0820] Polyurethanes are designated aromatic or aliphatic on the
basis of the chemical nature of the diisocyanate component in their
formulation. Tecoflex, Tecophilic and Carbothane resins are
manufactured using the aliphatic compound, hydrogenated methylene
diisocyanate (HMDI). Tecothane and Tecoplast resins use the
aromatic compound methylene diisocyanate (MDI). All the
formulations, with the exception of Carbothane, are formulated
using polytetramethylene ether glycol (PTMEG) and 1,4 butanediol
chain extender. Carbothane is specifically formulated with a
polycarbonate diol (PCDO).
[0821] These represent the major chemical composition differences
among the various families. Aromatic and aliphatic polyurethanes
share similar properties that make them outstanding materials for
use in medical devices. In general, there is not much difference
between medical grade aliphatic and aromatic polyurethanes with
regard to the following chemical, mechanical and biological
properties: [0822] High tensile strength (4,000 10,000 psi) [0823]
High ultimate elongation (250 700%) [0824] Wide range of durometer
(72 Shore A to 84 Shore D) [0825] Good biocompatibility [0826] High
abrasion resistance [0827] Good hydrolytic stability [0828] Can be
sterilized with ethylene oxide and gamma irradiation [0829]
Retention of elastomeric properties at low temperature [0830] Good
melt processing characteristics for extrusion, injection molding,
etc.
[0831] With such an impressive array of desirable features, it is
no wonder that both aliphatic and aromatic polyurethanes have
become increasingly the material of choice in the design of medical
grade components. There are, however, distinct differences between
these two families of polyurethane that could dictate the selection
of one over the other for a particular application:
Yellowing
[0832] In their natural states, both aromatic and aliphatic
polyurethanes are clear to very light yellow in color. Aromatics,
however, can turn dark yellow to amber as a result of melt
processing or sterilization, or even with age. Although the primary
objection to the discoloration of aromatic clear tubing or
injection molded parts is aesthetic, the yellowing, which is caused
by the formation of a chromophore in the MDI portion of the
polymer, does not appear to affect other physical properties of the
material. Radiopaque grades of Tecothane also exhibit some
discoloration during melt processing or sterilization. However,
both standard and custom compounded radiopaque grades of Tecothane
have been specifically formulated to minimize this
discoloration.
Solvent Resistance
[0833] Aromatic polyurethanes exhibit better resistance to organic
solvents and oils than do aliphatics--especially as compared with
low durometer (80 85 Shore A) aliphatics, where prolonged contact
can lead to swelling of the polymer and short-term contact can lead
to surface tackiness. While these effects become less noticeable at
higher durometers, aromatics exhibit little or no sensitivity upon
exposure to the common organic solvents used in the health care
industry.
Softening at Body Temperature
[0834] Both aliphatic and aromatic polyether-based polyurethanes
soften considerably within minutes of insertion in the body. Many
device manufacturers promote this feature of their urethane
products because of patient comfort advantage as well as the
reduced risk of vascular trauma. However, this softening effect is
less pronounced with aromatic resins than with aliphatic
resins.
Melt Processing Temperatures
[0835] Tecothane, Tecoplast and Carbothane melt at temperatures
considerably higher than Tecoflex and Tecophilic. Therefore,
processing by either extrusion or injection molding puts more heat
history into products manufactured from Tecothane, Tecoplast and
Carbothane. For example, Tecoflex EG-80A and EG-60D resins mold at
nozzle temperatures of approximately 310.degree. F. and 340.degree.
F. respectively.
[0836] Tecothane and Carbothane products of equivalent durometers
mold at nozzle temperatures in the range of 380.degree. F. to
435.degree. F.
Tecoflex.RTM.
[0837] A family of aliphatic, polyether-based TPU's. These resins
are easy to process and do not yellow upon aging. Solution grade
versions are candidates to replace latex.
Tecothane.RTM.
[0838] A family of aromatic, polyether-based TPU's available over a
wide range of durometers, colors, and radiopacifiers. One can
expect Tecothane resins to exhibit improved solvent resistance and
biostability when compared with Tecoflex resins of equal
durometers.
Carbothane.RTM.
[0839] A family of aliphatic, polycarbonate-based TPU's available
over a wide range of durometers, colors, and radiopacifiers. This
type of TPU has been reported to exhibit excellent oxidative
stability, a property which may equate to excellent long-term
biostability. This family, like Tecoflex, is easy to process and
does not yellow upon aging.
Tecophilic.RTM.
[0840] A family of aliphatic, polyether-based TPU's which have been
specially formulated to absorb equilibrium water contents of up to
150% of the weight of dry resin.
[0841] Tecogel, a new member to the Tecophilic family, is a
hydrogel that can be formulated to absorb equilibrium water
contents between 500% and 2000% of the weight of dry resin. The
materials were designed as a coating cast from an ethanol/water
solvent system.
Tecoplast.RTM.
[0842] A family of aromatic, polyether-based TPU's formulated to
produce rugged injection molded components exhibiting high
durometers and heat deflection temperatures.
[0843] Four families of polyurethanes, named Elast-Eon.TM., are
available from AorTech Biomaterials.
[0844] Elast-Eon.TM. 1, a Polyhexamethylene oxide (PHMO), aromatic
polyurethane, is an improvement on conventional polyurethane in
that it has a reduced number of the susceptible chemical groups.
Elast-Eon.TM. 2, a Siloxane based macrodiol, aromatic polyurethane,
incorporates siloxane into the soft segment. Elast-Eon.TM. 3, a
Siloxane based macrodiol, modified hard segment, aromatic
polyurethane, is a variation of Elast-Eon.TM. 2 with further
enhanced flexibility due to incorporation of siloxane into the hard
segment. Elast-Eon.TM. 4 is a modified aromatic hard segment
polyurethane.
[0845] The following materials are manufactured by Bayer
Corporation:
[0846] Texin 4210--Thermoplastic polyurethane/polycarbonate blend
for injection molding and extrusion.
[0847] Texin 4215--Thermoplastic polyurethane/polycarbonate blend
for injection molding and extrusion.
[0848] Texin 5250--Aromatic polyether-based medical grade with a
Shore D hardness of approximately 50 for injection molding and
extrusion. Complies with 21 CFR 177.1680 and 177.2600.
[0849] Texin 5286--Aromatic polyether-based medical grade with
Shore A hardness of approximately 86 for injection molding or
extrusion. Complies with 21 CFR 177.1680 and 177.2600.
[0850] Texin 5290--Aromatic polyether-based medical grade with a
Shore A hardness of approximately 90. Complies with 21 CFR 177.1680
and 177.2600.
[0851] It is appreciated that the devices described hereinabove,
while preferably formed by injection molding of polyurethane, may
also be formed by any suitable manufacturing method and may be
formed of any suitable medical grade elastomers. It is further
appreciated that any of the following manufacturing methods may be
utilized: injection molding including inserting inserts,
compression molding including inserting inserts,
injection--compression molding including inserting inserts,
compression molding of prefabricated elements pre-formed by any of
the above methods including inserting inserts, spraying including
inserting inserts, dipping including inserting inserts, machining
from stock or rods, machining from prefabricated elements including
inserting inserts.
[0852] It is appreciated by persons skilled in the art that the
present invention is not limited by what has been particularly
shown and described hereinabove. Rather the scope of the present
invention includes both combinations and subcombinations of various
features described hereinabove as well as variations and
modifications thereto which would occur to a person of skill in the
art upon reading the above description and which are not in the
prior art.
* * * * *